diff --git a/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/app/routes.ts b/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/app/routes.ts
index 6bd5b27264eb..477336455452 100644
--- a/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/app/routes.ts
+++ b/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/app/routes.ts
@@ -10,6 +10,8 @@ export default [
     route('server-loader', 'routes/performance/server-loader.tsx'),
     route('server-action', 'routes/performance/server-action.tsx'),
     route('with-middleware', 'routes/performance/with-middleware.tsx'),
+    route('multi-middleware', 'routes/performance/multi-middleware.tsx'),
+    route('other-middleware', 'routes/performance/other-middleware.tsx'),
     route('error-loader', 'routes/performance/error-loader.tsx'),
     route('error-action', 'routes/performance/error-action.tsx'),
     route('error-middleware', 'routes/performance/error-middleware.tsx'),
diff --git a/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/app/routes/performance/multi-middleware.tsx b/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/app/routes/performance/multi-middleware.tsx
new file mode 100644
index 000000000000..4b43ad619901
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/app/routes/performance/multi-middleware.tsx
@@ -0,0 +1,34 @@
+import type { Route } from './+types/multi-middleware';
+
+// Multiple middleware functions to test index tracking
+// Using unique names to avoid bundler renaming due to collisions with other routes
+export const middleware: Route.MiddlewareFunction[] = [
+  async function multiAuthMiddleware({ context }, next) {
+    (context as any).auth = true;
+    const response = await next();
+    return response;
+  },
+  async function multiLoggingMiddleware({ context }, next) {
+    (context as any).logged = true;
+    const response = await next();
+    return response;
+  },
+  async function multiValidationMiddleware({ context }, next) {
+    (context as any).validated = true;
+    const response = await next();
+    return response;
+  },
+];
+
+export function loader() {
+  return { message: 'Multi-middleware route loaded' };
+}
+
+export default function MultiMiddlewarePage() {
+  return (
+    <div>
+      <h1 id="multi-middleware-title">Multi Middleware Route</h1>
+      <p id="multi-middleware-content">This route has 3 middlewares</p>
+    </div>
+  );
+}
diff --git a/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/app/routes/performance/other-middleware.tsx b/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/app/routes/performance/other-middleware.tsx
new file mode 100644
index 000000000000..7f68cd35e314
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/app/routes/performance/other-middleware.tsx
@@ -0,0 +1,23 @@
+import type { Route } from './+types/other-middleware';
+
+// Different middleware to test isolation between routes
+export const middleware: Route.MiddlewareFunction[] = [
+  async function rateLimitMiddleware({ context }, next) {
+    (context as any).rateLimited = false;
+    const response = await next();
+    return response;
+  },
+];
+
+export function loader() {
+  return { message: 'Other middleware route loaded' };
+}
+
+export default function OtherMiddlewarePage() {
+  return (
+    <div>
+      <h1 id="other-middleware-title">Other Middleware Route</h1>
+      <p id="other-middleware-content">This route has a different middleware</p>
+    </div>
+  );
+}
diff --git a/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/instrument.mjs b/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/instrument.mjs
index bb1dad2e5da9..0465d1516529 100644
--- a/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/instrument.mjs
+++ b/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/instrument.mjs
@@ -1,3 +1,8 @@
+// Register ESM hooks before importing any other modules.
+// This is required on Node 20.19+ and 22.12+ for OTEL module patching to work.
+// Without this, middleware function names won't be captured.
+import '@sentry/react-router/loader';
+
 import * as Sentry from '@sentry/react-router';
 
 // Initialize Sentry early (before the server starts)
diff --git a/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/tests/performance/middleware.server.test.ts b/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/tests/performance/middleware.server.test.ts
index e99a58a7f57c..f13c9dd5227c 100644
--- a/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/tests/performance/middleware.server.test.ts
+++ b/dev-packages/e2e-tests/test-applications/react-router-7-framework-instrumentation/tests/performance/middleware.server.test.ts
@@ -2,8 +2,28 @@ import { expect, test } from '@playwright/test';
 import { waitForTransaction } from '@sentry-internal/test-utils';
 import { APP_NAME } from '../constants';
 
-// Note: React Router middleware instrumentation now works in Framework Mode.
-// Previously this was a known limitation (see: https://github.com/remix-run/react-router/discussions/12950)
+interface SpanData {
+  'sentry.op'?: string;
+  'sentry.origin'?: string;
+  'react_router.route.id'?: string;
+  'react_router.route.pattern'?: string;
+  'react_router.middleware.name'?: string;
+  'react_router.middleware.index'?: number;
+}
+
+interface Span {
+  span_id?: string;
+  trace_id?: string;
+  data?: SpanData;
+  description?: string;
+  parent_span_id?: string;
+  start_timestamp?: number;
+  timestamp?: number;
+  op?: string;
+  origin?: string;
+}
+
+// Middleware names require ESM loader hook on Node 20.19+/22.12+ - see instrument.mjs for setup.
 test.describe('server - instrumentation API middleware', () => {
   test('should instrument server middleware with instrumentation API origin', async ({ page }) => {
     const txPromise = waitForTransaction(APP_NAME, async transactionEvent => {
@@ -40,23 +60,30 @@ test.describe('server - instrumentation API middleware', () => {
 
     // Find the middleware span
     const middlewareSpan = transaction?.spans?.find(
-      (span: { data?: { 'sentry.op'?: string } }) => span.data?.['sentry.op'] === 'function.react_router.middleware',
+      (span: Span) => span.data?.['sentry.op'] === 'function.react_router.middleware',
     );
 
+    expect(middlewareSpan).toBeDefined();
     expect(middlewareSpan).toMatchObject({
       span_id: expect.any(String),
       trace_id: expect.any(String),
-      data: {
+      data: expect.objectContaining({
         'sentry.origin': 'auto.function.react_router.instrumentation_api',
         'sentry.op': 'function.react_router.middleware',
-      },
-      description: '/performance/with-middleware',
+        'react_router.route.id': 'routes/performance/with-middleware',
+        'react_router.route.pattern': '/performance/with-middleware',
+        'react_router.middleware.index': 0,
+      }),
       parent_span_id: expect.any(String),
       start_timestamp: expect.any(Number),
       timestamp: expect.any(Number),
       op: 'function.react_router.middleware',
       origin: 'auto.function.react_router.instrumentation_api',
     });
+
+    // Middleware name is available via OTEL patching of createRequestHandler
+    expect(middlewareSpan!.data?.['react_router.middleware.name']).toBe('authMiddleware');
+    expect(middlewareSpan!.description).toBe('middleware authMiddleware');
   });
 
   test('should have middleware span run before loader span', async ({ page }) => {
@@ -69,17 +96,162 @@ test.describe('server - instrumentation API middleware', () => {
     const transaction = await txPromise;
 
     const middlewareSpan = transaction?.spans?.find(
-      (span: { data?: { 'sentry.op'?: string } }) => span.data?.['sentry.op'] === 'function.react_router.middleware',
+      (span: Span) => span.data?.['sentry.op'] === 'function.react_router.middleware',
     );
 
     const loaderSpan = transaction?.spans?.find(
-      (span: { data?: { 'sentry.op'?: string } }) => span.data?.['sentry.op'] === 'function.react_router.loader',
+      (span: Span) => span.data?.['sentry.op'] === 'function.react_router.loader',
     );
 
     expect(middlewareSpan).toBeDefined();
     expect(loaderSpan).toBeDefined();
 
     // Middleware should start before loader
-    expect(middlewareSpan!.start_timestamp).toBeLessThanOrEqual(loaderSpan!.start_timestamp);
+    expect(middlewareSpan!.start_timestamp).toBeLessThanOrEqual(loaderSpan!.start_timestamp!);
+  });
+
+  test('should track multiple middlewares with correct indices', async ({ page }) => {
+    const txPromise = waitForTransaction(APP_NAME, async transactionEvent => {
+      return transactionEvent.transaction === 'GET /performance/multi-middleware';
+    });
+
+    await page.goto(`/performance/multi-middleware`);
+
+    const transaction = await txPromise;
+
+    // Verify the page rendered
+    await expect(page.locator('#multi-middleware-title')).toBeVisible();
+    await expect(page.locator('#multi-middleware-content')).toHaveText('This route has 3 middlewares');
+
+    // Find all middleware spans
+    const middlewareSpans = transaction?.spans?.filter(
+      (span: Span) => span.data?.['sentry.op'] === 'function.react_router.middleware',
+    );
+
+    expect(middlewareSpans).toHaveLength(3);
+
+    // Sort by index to ensure correct order
+    const sortedSpans = [...middlewareSpans!].sort(
+      (a: Span, b: Span) =>
+        (a.data?.['react_router.middleware.index'] ?? 0) - (b.data?.['react_router.middleware.index'] ?? 0),
+    );
+
+    // First middleware (index 0)
+    expect(sortedSpans[0]).toMatchObject({
+      data: expect.objectContaining({
+        'sentry.op': 'function.react_router.middleware',
+        'react_router.route.id': 'routes/performance/multi-middleware',
+        'react_router.route.pattern': '/performance/multi-middleware',
+        'react_router.middleware.index': 0,
+      }),
+    });
+
+    // Second middleware (index 1)
+    expect(sortedSpans[1]).toMatchObject({
+      data: expect.objectContaining({
+        'sentry.op': 'function.react_router.middleware',
+        'react_router.route.id': 'routes/performance/multi-middleware',
+        'react_router.route.pattern': '/performance/multi-middleware',
+        'react_router.middleware.index': 1,
+      }),
+    });
+
+    // Third middleware (index 2)
+    expect(sortedSpans[2]).toMatchObject({
+      data: expect.objectContaining({
+        'sentry.op': 'function.react_router.middleware',
+        'react_router.route.id': 'routes/performance/multi-middleware',
+        'react_router.route.pattern': '/performance/multi-middleware',
+        'react_router.middleware.index': 2,
+      }),
+    });
+
+    // Verify execution order: middleware spans should be sequential
+    expect(sortedSpans[0]!.start_timestamp).toBeLessThanOrEqual(sortedSpans[1]!.start_timestamp!);
+    expect(sortedSpans[1]!.start_timestamp).toBeLessThanOrEqual(sortedSpans[2]!.start_timestamp!);
+
+    // Verify middleware names are correctly resolved via OTEL patching
+    expect(sortedSpans[0]!.data?.['react_router.middleware.name']).toBe('multiAuthMiddleware');
+    expect(sortedSpans[1]!.data?.['react_router.middleware.name']).toBe('multiLoggingMiddleware');
+    expect(sortedSpans[2]!.data?.['react_router.middleware.name']).toBe('multiValidationMiddleware');
+  });
+
+  // Note: Remaining tests focus on index tracking. Name resolution is verified above.
+  test('should isolate middleware indices between different routes', async ({ page }) => {
+    // First visit the route with different middleware
+    const txPromise1 = waitForTransaction(APP_NAME, async transactionEvent => {
+      return transactionEvent.transaction === 'GET /performance/other-middleware';
+    });
+
+    await page.goto(`/performance/other-middleware`);
+
+    const transaction1 = await txPromise1;
+
+    // Verify the page rendered
+    await expect(page.locator('#other-middleware-title')).toBeVisible();
+
+    // Find the middleware span
+    const middlewareSpan1 = transaction1?.spans?.find(
+      (span: Span) => span.data?.['sentry.op'] === 'function.react_router.middleware',
+    );
+
+    // The other route should have its own middleware with index 0
+    expect(middlewareSpan1).toMatchObject({
+      data: expect.objectContaining({
+        'sentry.op': 'function.react_router.middleware',
+        'react_router.route.id': 'routes/performance/other-middleware',
+        'react_router.route.pattern': '/performance/other-middleware',
+        'react_router.middleware.index': 0,
+      }),
+    });
+
+    // Now visit the multi-middleware route
+    const txPromise2 = waitForTransaction(APP_NAME, async transactionEvent => {
+      return transactionEvent.transaction === 'GET /performance/multi-middleware';
+    });
+
+    await page.goto(`/performance/multi-middleware`);
+
+    const transaction2 = await txPromise2;
+
+    // Find all middleware spans
+    const middlewareSpans2 = transaction2?.spans?.filter(
+      (span: Span) => span.data?.['sentry.op'] === 'function.react_router.middleware',
+    );
+
+    // Should have 3 middleware spans with indices 0, 1, 2 (isolated from previous route)
+    expect(middlewareSpans2).toHaveLength(3);
+
+    const indices = middlewareSpans2!.map((span: Span) => span.data?.['react_router.middleware.index']).sort();
+    expect(indices).toEqual([0, 1, 2]);
+  });
+
+  test('should handle visiting same multi-middleware route twice with fresh indices', async ({ page }) => {
+    // First visit
+    const txPromise1 = waitForTransaction(APP_NAME, async transactionEvent => {
+      return transactionEvent.transaction === 'GET /performance/multi-middleware';
+    });
+
+    await page.goto(`/performance/multi-middleware`);
+    await txPromise1;
+
+    // Second visit - indices should reset
+    const txPromise2 = waitForTransaction(APP_NAME, async transactionEvent => {
+      return transactionEvent.transaction === 'GET /performance/multi-middleware';
+    });
+
+    await page.goto(`/performance/multi-middleware`);
+
+    const transaction2 = await txPromise2;
+
+    const middlewareSpans = transaction2?.spans?.filter(
+      (span: Span) => span.data?.['sentry.op'] === 'function.react_router.middleware',
+    );
+
+    expect(middlewareSpans).toHaveLength(3);
+
+    // Indices should be 0, 1, 2 (reset for new request)
+    const indices = middlewareSpans!.map((span: Span) => span.data?.['react_router.middleware.index']).sort();
+    expect(indices).toEqual([0, 1, 2]);
   });
 });
diff --git a/dev-packages/rollup-utils/code/sentryNodeEsmLoaderHookTemplate.js b/dev-packages/rollup-utils/code/sentryNodeEsmLoaderHookTemplate.js
index d5167fd15bf9..84f636c923f5 100644
--- a/dev-packages/rollup-utils/code/sentryNodeEsmLoaderHookTemplate.js
+++ b/dev-packages/rollup-utils/code/sentryNodeEsmLoaderHookTemplate.js
@@ -1 +1 @@
-import '@sentry/node/import-hook';
+import '@sentry/node/import';
diff --git a/packages/react-router/package.json b/packages/react-router/package.json
index 7ab6dd30b03b..fe46288657b4 100644
--- a/packages/react-router/package.json
+++ b/packages/react-router/package.json
@@ -39,6 +39,16 @@
       "require": "./build/cjs/cloudflare/index.js",
       "types": "./build/types/cloudflare/index.d.ts",
       "default": "./build/esm/cloudflare/index.js"
+    },
+    "./import": {
+      "import": {
+        "default": "./build/import-hook.mjs"
+      }
+    },
+    "./loader": {
+      "import": {
+        "default": "./build/loader-hook.mjs"
+      }
     }
   },
   "publishConfig": {
diff --git a/packages/react-router/rollup.npm.config.mjs b/packages/react-router/rollup.npm.config.mjs
index 4a52f4ab57a7..10fd9467a79a 100644
--- a/packages/react-router/rollup.npm.config.mjs
+++ b/packages/react-router/rollup.npm.config.mjs
@@ -1,4 +1,4 @@
-import { makeBaseNPMConfig, makeNPMConfigVariants } from '@sentry-internal/rollup-utils';
+import { makeBaseNPMConfig, makeNPMConfigVariants, makeOtelLoaders } from '@sentry-internal/rollup-utils';
 
 export default [
   ...makeNPMConfigVariants(
@@ -19,4 +19,5 @@ export default [
       },
     }),
   ),
+  ...makeOtelLoaders('./build', 'sentry-node'),
 ];
diff --git a/packages/react-router/src/client/createClientInstrumentation.ts b/packages/react-router/src/client/createClientInstrumentation.ts
index c465a25dd662..888f9e879416 100644
--- a/packages/react-router/src/client/createClientInstrumentation.ts
+++ b/packages/react-router/src/client/createClientInstrumentation.ts
@@ -19,6 +19,10 @@ const WINDOW = GLOBAL_OBJ as typeof GLOBAL_OBJ & Window;
 // Tracks active numeric navigation span to prevent duplicate spans when popstate fires
 let currentNumericNavigationSpan: Span | undefined;
 
+// Tracks middleware execution index per route, keyed by Request object.
+// Uses WeakMap to isolate counters per navigation and allow GC of cancelled navigations.
+const middlewareCountersMap = new WeakMap<object, Record<string, number>>();
+
 const SENTRY_CLIENT_INSTRUMENTATION_FLAG = '__sentryReactRouterClientInstrumentationUsed';
 // Intentionally never reset - once set, instrumentation API handles all navigations for the session.
 const SENTRY_NAVIGATE_HOOK_INVOKED_FLAG = '__sentryReactRouterNavigateHookInvoked';
@@ -214,6 +218,8 @@ export function createSentryClientInstrumentation(
     },
 
     route(route: InstrumentableRoute) {
+      const routeId = route.id;
+
       route.instrument({
         async loader(callLoader, info) {
           const urlPath = getPathFromRequest(info.request);
@@ -267,12 +273,33 @@ export function createSentryClientInstrumentation(
           const urlPath = getPathFromRequest(info.request);
           const routePattern = normalizeRoutePath(getPattern(info)) || urlPath;
 
+          // Get or create counters for this navigation's Request
+          let counters = middlewareCountersMap.get(info.request);
+          if (!counters) {
+            counters = {};
+            middlewareCountersMap.set(info.request, counters);
+          }
+
+          // Get middleware index and increment for next middleware
+          const middlewareIndex = counters[routeId] ?? 0;
+          counters[routeId] = middlewareIndex + 1;
+
+          // Try to get the actual middleware function name
+          const middlewareName = getClientMiddlewareName(routeId, middlewareIndex);
+
+          // Build display name: prefer function name, fallback to routeId
+          const displayName = middlewareName || routeId;
+
           await startSpan(
             {
-              name: routePattern,
+              name: `middleware ${displayName}`,
               attributes: {
                 [SEMANTIC_ATTRIBUTE_SENTRY_OP]: 'function.react_router.client_middleware',
                 [SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: 'auto.function.react_router.instrumentation_api',
+                'react_router.route.id': routeId,
+                'react_router.route.pattern': routePattern,
+                ...(middlewareName && { 'react_router.middleware.name': middlewareName }),
+                'react_router.middleware.index': middlewareIndex,
               },
             },
             async span => {
@@ -325,3 +352,30 @@ export function isClientInstrumentationApiUsed(): boolean {
 export function isNavigateHookInvoked(): boolean {
   return !!GLOBAL_WITH_FLAGS[SENTRY_NAVIGATE_HOOK_INVOKED_FLAG];
 }
+
+interface RouteModule {
+  [key: string]: unknown;
+  clientMiddleware?: Array<{ name?: string }>;
+}
+
+interface GlobalObjWithRouteModules {
+  __reactRouterRouteModules?: Record<string, RouteModule>;
+}
+
+/**
+ * Get client middleware function name from __reactRouterRouteModules.
+ * @internal
+ */
+function getClientMiddlewareName(routeId: string, index: number): string | undefined {
+  const globalWithModules = GLOBAL_OBJ as typeof GLOBAL_OBJ & GlobalObjWithRouteModules;
+  const routeModules = globalWithModules.__reactRouterRouteModules;
+  if (!routeModules) return undefined;
+
+  const routeModule = routeModules[routeId];
+  // Client middleware is exposed as clientMiddleware in route modules
+  const clientMiddleware = routeModule?.clientMiddleware;
+  if (!Array.isArray(clientMiddleware)) return undefined;
+
+  const middlewareFn = clientMiddleware[index];
+  return middlewareFn?.name || undefined;
+}
diff --git a/packages/react-router/src/server/createServerInstrumentation.ts b/packages/react-router/src/server/createServerInstrumentation.ts
index 3fceca6a4ff7..4f1e430d2988 100644
--- a/packages/react-router/src/server/createServerInstrumentation.ts
+++ b/packages/react-router/src/server/createServerInstrumentation.ts
@@ -1,4 +1,4 @@
-import { context } from '@opentelemetry/api';
+import { context, createContextKey } from '@opentelemetry/api';
 import { getRPCMetadata, RPCType } from '@opentelemetry/core';
 import { ATTR_HTTP_ROUTE } from '@opentelemetry/semantic-conventions';
 import {
@@ -17,8 +17,17 @@ import {
 import { DEBUG_BUILD } from '../common/debug-build';
 import type { InstrumentableRequestHandler, InstrumentableRoute, ServerInstrumentation } from '../common/types';
 import { captureInstrumentationError, getPathFromRequest, getPattern, normalizeRoutePath } from '../common/utils';
+import { getMiddlewareName } from './serverBuild';
 import { markInstrumentationApiUsed } from './serverGlobals';
 
+// OTel context key for tracking middleware execution index per route
+const MIDDLEWARE_COUNTER_KEY = createContextKey('sentry_react_router_middleware_counter');
+
+interface MiddlewareCounterStore {
+  // Maps routeId to current middleware index
+  counters: Record<string, number>;
+}
+
 // Re-export for backward compatibility and external use
 export { isInstrumentationApiUsed } from './serverGlobals';
 
@@ -53,6 +62,10 @@ export function createSentryServerInstrumentation(
           const activeSpan = getActiveSpan();
           const existingRootSpan = activeSpan ? getRootSpan(activeSpan) : undefined;
 
+          // Initialize middleware counter for this request
+          const counterStore: MiddlewareCounterStore = { counters: {} };
+          const ctx = context.active().setValue(MIDDLEWARE_COUNTER_KEY, counterStore);
+
           if (existingRootSpan) {
             updateSpanName(existingRootSpan, `${info.request.method} ${pathname}`);
             existingRootSpan.setAttributes({
@@ -61,53 +74,59 @@ export function createSentryServerInstrumentation(
               [SEMANTIC_ATTRIBUTE_SENTRY_SOURCE]: 'url',
             });
 
-            try {
-              const result = await handleRequest();
-              if (result.status === 'error' && result.error instanceof Error) {
-                existingRootSpan.setStatus({ code: SPAN_STATUS_ERROR, message: 'internal_error' });
-                captureInstrumentationError(result, captureErrors, 'react_router.request_handler', {
-                  'http.method': info.request.method,
-                  'http.url': pathname,
-                });
+            await context.with(ctx, async () => {
+              try {
+                const result = await handleRequest();
+                if (result.status === 'error' && result.error instanceof Error) {
+                  existingRootSpan.setStatus({ code: SPAN_STATUS_ERROR, message: 'internal_error' });
+                  captureInstrumentationError(result, captureErrors, 'react_router.request_handler', {
+                    'http.method': info.request.method,
+                    'http.url': pathname,
+                  });
+                }
+              } finally {
+                await flushIfServerless();
               }
-            } finally {
-              await flushIfServerless();
-            }
+            });
           } else {
-            await startSpan(
-              {
-                name: `${info.request.method} ${pathname}`,
-                forceTransaction: true,
-                attributes: {
-                  [SEMANTIC_ATTRIBUTE_SENTRY_OP]: 'http.server',
-                  [SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: 'auto.http.react_router.instrumentation_api',
-                  [SEMANTIC_ATTRIBUTE_SENTRY_SOURCE]: 'url',
-                  'http.request.method': info.request.method,
-                  'url.path': pathname,
-                  'url.full': info.request.url,
+            await context.with(ctx, async () => {
+              await startSpan(
+                {
+                  name: `${info.request.method} ${pathname}`,
+                  forceTransaction: true,
+                  attributes: {
+                    [SEMANTIC_ATTRIBUTE_SENTRY_OP]: 'http.server',
+                    [SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: 'auto.http.react_router.instrumentation_api',
+                    [SEMANTIC_ATTRIBUTE_SENTRY_SOURCE]: 'url',
+                    'http.request.method': info.request.method,
+                    'url.path': pathname,
+                    'url.full': info.request.url,
+                  },
                 },
-              },
-              async span => {
-                try {
-                  const result = await handleRequest();
-                  if (result.status === 'error' && result.error instanceof Error) {
-                    span.setStatus({ code: SPAN_STATUS_ERROR, message: 'internal_error' });
-                    captureInstrumentationError(result, captureErrors, 'react_router.request_handler', {
-                      'http.method': info.request.method,
-                      'http.url': pathname,
-                    });
+                async span => {
+                  try {
+                    const result = await handleRequest();
+                    if (result.status === 'error' && result.error instanceof Error) {
+                      span.setStatus({ code: SPAN_STATUS_ERROR, message: 'internal_error' });
+                      captureInstrumentationError(result, captureErrors, 'react_router.request_handler', {
+                        'http.method': info.request.method,
+                        'http.url': pathname,
+                      });
+                    }
+                  } finally {
+                    await flushIfServerless();
                   }
-                } finally {
-                  await flushIfServerless();
-                }
-              },
-            );
+                },
+              );
+            });
           }
         },
       });
     },
 
     route(route: InstrumentableRoute) {
+      const routeId = route.id;
+
       route.instrument({
         async loader(callLoader, info) {
           const urlPath = getPathFromRequest(info.request);
@@ -168,15 +187,28 @@ export function createSentryServerInstrumentation(
           const pattern = getPattern(info);
           const routePattern = normalizeRoutePath(pattern) || urlPath;
 
-          // Update root span with parameterized route (same as loader/action)
           updateRootSpanWithRoute(info.request.method, pattern, urlPath);
 
+          const counterStore = context.active().getValue(MIDDLEWARE_COUNTER_KEY) as MiddlewareCounterStore | undefined;
+          let middlewareIndex = 0;
+          if (counterStore) {
+            middlewareIndex = counterStore.counters[routeId] ?? 0;
+            counterStore.counters[routeId] = middlewareIndex + 1;
+          }
+
+          const middlewareName = getMiddlewareName(routeId, middlewareIndex);
+          const displayName = middlewareName || routeId;
+
           await startSpan(
             {
-              name: routePattern,
+              name: `middleware ${displayName}`,
               attributes: {
                 [SEMANTIC_ATTRIBUTE_SENTRY_OP]: 'function.react_router.middleware',
                 [SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: 'auto.function.react_router.instrumentation_api',
+                'react_router.route.id': routeId,
+                'react_router.route.pattern': routePattern,
+                ...(middlewareName && { 'react_router.middleware.name': middlewareName }),
+                'react_router.middleware.index': middlewareIndex,
               },
             },
             async span => {
diff --git a/packages/react-router/src/server/instrumentation/reactRouter.ts b/packages/react-router/src/server/instrumentation/reactRouter.ts
index 2f24d2c7bcb7..68e648edf7a2 100644
--- a/packages/react-router/src/server/instrumentation/reactRouter.ts
+++ b/packages/react-router/src/server/instrumentation/reactRouter.ts
@@ -15,6 +15,7 @@ import {
 } from '@sentry/core';
 import type * as reactRouter from 'react-router';
 import { DEBUG_BUILD } from '../../common/debug-build';
+import { isServerBuildLike, setServerBuild } from '../serverBuild';
 import { isInstrumentationApiUsed } from '../serverGlobals';
 import { getOpName, getSpanName, isDataRequest } from './util';
 
@@ -62,8 +63,20 @@ export class ReactRouterInstrumentation extends InstrumentationBase<Instrumentat
         if (prop === 'createRequestHandler') {
           const original = target[prop];
           return function sentryWrappedCreateRequestHandler(this: unknown, ...args: unknown[]) {
+            // Capture the ServerBuild reference for middleware name lookup
+            const build = args[0];
+            if (isServerBuildLike(build)) {
+              setServerBuild(build);
+            }
+
             const originalRequestHandler = original.apply(this, args);
 
+            // Skip per-request wrapping if instrumentation API handles tracing
+            // This avoids overhead on every request when instrumentation API is active
+            if (isInstrumentationApiUsed()) {
+              return originalRequestHandler;
+            }
+
             return async function sentryWrappedRequestHandler(request: Request, initialContext?: unknown) {
               let url: URL;
               try {
@@ -77,13 +90,6 @@ export class ReactRouterInstrumentation extends InstrumentationBase<Instrumentat
                 return originalRequestHandler(request, initialContext);
               }
 
-              // Skip OTEL instrumentation if instrumentation API is being used
-              // as it handles loader/action spans itself
-              if (isInstrumentationApiUsed()) {
-                DEBUG_BUILD && debug.log('Skipping OTEL loader/action instrumentation - using instrumentation API');
-                return originalRequestHandler(request, initialContext);
-              }
-
               const activeSpan = getActiveSpan();
               const rootSpan = activeSpan && getRootSpan(activeSpan);
 
diff --git a/packages/react-router/src/server/integration/reactRouterServer.ts b/packages/react-router/src/server/integration/reactRouterServer.ts
index 1789109facf3..2a31d2b46dac 100644
--- a/packages/react-router/src/server/integration/reactRouterServer.ts
+++ b/packages/react-router/src/server/integration/reactRouterServer.ts
@@ -1,8 +1,7 @@
 import { ATTR_HTTP_ROUTE } from '@opentelemetry/semantic-conventions';
 import { defineIntegration } from '@sentry/core';
-import { generateInstrumentOnce, NODE_VERSION } from '@sentry/node';
+import { generateInstrumentOnce } from '@sentry/node';
 import { ReactRouterInstrumentation } from '../instrumentation/reactRouter';
-import { isInstrumentationApiUsed } from '../serverGlobals';
 
 const INTEGRATION_NAME = 'ReactRouterServer';
 
@@ -24,17 +23,11 @@ export const reactRouterServerIntegration = defineIntegration(() => {
   return {
     name: INTEGRATION_NAME,
     setupOnce() {
-      // Skip OTEL patching if the instrumentation API is in use
-      if (isInstrumentationApiUsed()) {
-        return;
-      }
-
-      if (
-        (NODE_VERSION.major === 20 && NODE_VERSION.minor < 19) || // https://nodejs.org/en/blog/release/v20.19.0
-        (NODE_VERSION.major === 22 && NODE_VERSION.minor < 12) // https://nodejs.org/en/blog/release/v22.12.0
-      ) {
-        instrumentReactRouterServer();
-      }
+      // Install OTEL instrumentation to capture ServerBuild for middleware name resolution.
+      // When instrumentation API is active, the wrapper captures ServerBuild but skips
+      // per-request wrapping. On Node 20.19+/22.12+, users must import
+      // '@sentry/react-router/loader' first for ESM patching; otherwise names fall back to routeId.
+      instrumentReactRouterServer();
     },
     processEvent(event) {
       // Express generates bogus `*` routes for data loaders, which we want to remove here
diff --git a/packages/react-router/src/server/serverBuild.ts b/packages/react-router/src/server/serverBuild.ts
new file mode 100644
index 000000000000..9126753d2231
--- /dev/null
+++ b/packages/react-router/src/server/serverBuild.ts
@@ -0,0 +1,66 @@
+/**
+ * Loose type for ServerBuild to access middleware properties
+ * that may not be in the official React Router types.
+ * @internal
+ */
+interface ServerBuildLike {
+  routes?: Record<
+    string,
+    {
+      id?: string;
+      module?: {
+        middleware?: Array<{ name?: string }>;
+      };
+    }
+  >;
+}
+
+// ServerBuild reference for middleware name lookup. Updated on each createRequestHandler call.
+let _serverBuild: ServerBuildLike | undefined;
+
+/**
+ * Type guard to check if an object is a ServerBuild-like structure.
+ * @internal
+ */
+export function isServerBuildLike(build: unknown): build is ServerBuildLike {
+  if (build === null || typeof build !== 'object' || !('routes' in build)) {
+    return false;
+  }
+  const routes = (build as { routes: unknown }).routes;
+  return routes !== null && typeof routes === 'object';
+}
+
+/**
+ * Stores reference to the React Router ServerBuild.
+ * Called when createRequestHandler is invoked.
+ * @internal
+ */
+export function setServerBuild(build: ServerBuildLike): void {
+  _serverBuild = build;
+}
+
+/**
+ * Looks up a middleware function name from the ServerBuild.
+ * @param routeId - The route ID
+ * @param index - The middleware function index within the route's middleware array
+ * @returns The middleware function name if available, undefined otherwise
+ * @internal
+ */
+export function getMiddlewareName(routeId: string, index: number): string | undefined {
+  if (!_serverBuild?.routes) return undefined;
+
+  const route = _serverBuild.routes[routeId];
+  if (!route?.module?.middleware) return undefined;
+
+  const middlewareFn = route.module.middleware[index];
+  return middlewareFn?.name || undefined;
+}
+
+/**
+ * Clears the stored ServerBuild reference.
+ * Only used for testing purposes.
+ * @internal
+ */
+export function _resetServerBuild(): void {
+  _serverBuild = undefined;
+}
diff --git a/packages/react-router/test/client/createClientInstrumentation.test.ts b/packages/react-router/test/client/createClientInstrumentation.test.ts
index 0078b2601c51..46db5a6191c2 100644
--- a/packages/react-router/test/client/createClientInstrumentation.test.ts
+++ b/packages/react-router/test/client/createClientInstrumentation.test.ts
@@ -453,7 +453,7 @@ describe('createSentryClientInstrumentation', () => {
     );
   });
 
-  it('should instrument route middleware with spans', async () => {
+  it('should instrument route middleware with spans (without function name)', async () => {
     const mockCallMiddleware = vi.fn().mockResolvedValue({ status: 'success', error: undefined });
     const mockInstrument = vi.fn();
 
@@ -478,14 +478,67 @@ describe('createSentryClientInstrumentation', () => {
 
     expect(core.startSpan).toHaveBeenCalledWith(
       expect.objectContaining({
-        name: '/users/:id',
+        name: 'middleware test-route',
         attributes: expect.objectContaining({
           'sentry.op': 'function.react_router.client_middleware',
           'sentry.origin': 'auto.function.react_router.instrumentation_api',
+          'react_router.route.id': 'test-route',
+          'react_router.route.pattern': '/users/:id',
+          'react_router.middleware.index': 0,
+        }),
+      }),
+      expect.any(Function),
+    );
+  });
+
+  it('should use middleware function name when available from window.__reactRouterRouteModules', async () => {
+    const mockCallMiddleware = vi.fn().mockResolvedValue({ status: 'success', error: undefined });
+    const mockInstrument = vi.fn();
+
+    // Use a unique route ID to avoid counter conflicts with other tests
+    const routeId = 'test-route-with-name';
+
+    // Mock window.__reactRouterRouteModules
+    (globalThis as any).__reactRouterRouteModules = {
+      [routeId]: {
+        clientMiddleware: [{ name: 'authClientMiddleware' }],
+      },
+    };
+
+    (core.startSpan as any).mockImplementation((_opts: any, fn: any) => fn());
+
+    const instrumentation = createSentryClientInstrumentation();
+    instrumentation.route?.({
+      id: routeId,
+      index: false,
+      path: '/users/:id',
+      instrument: mockInstrument,
+    });
+
+    const hooks = mockInstrument.mock.calls[0]![0];
+
+    await hooks.middleware(mockCallMiddleware, {
+      request: { method: 'GET', url: 'http://example.com/users/123', headers: { get: () => null } },
+      params: { id: '123' },
+      unstable_pattern: '/users/:id',
+      context: undefined,
+    });
+
+    expect(core.startSpan).toHaveBeenCalledWith(
+      expect.objectContaining({
+        name: 'middleware authClientMiddleware',
+        attributes: expect.objectContaining({
+          'sentry.op': 'function.react_router.client_middleware',
+          'react_router.route.id': routeId,
+          'react_router.middleware.name': 'authClientMiddleware',
+          'react_router.middleware.index': 0,
         }),
       }),
       expect.any(Function),
     );
+
+    // Cleanup
+    delete (globalThis as any).__reactRouterRouteModules;
   });
 
   it('should instrument lazy route loading with spans', async () => {
diff --git a/packages/react-router/test/server/createServerInstrumentation.test.ts b/packages/react-router/test/server/createServerInstrumentation.test.ts
index 33eb73f48ace..14937d82c158 100644
--- a/packages/react-router/test/server/createServerInstrumentation.test.ts
+++ b/packages/react-router/test/server/createServerInstrumentation.test.ts
@@ -1,9 +1,11 @@
+import * as otelApi from '@opentelemetry/api';
 import * as core from '@sentry/core';
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import {
   createSentryServerInstrumentation,
   isInstrumentationApiUsed,
 } from '../../src/server/createServerInstrumentation';
+import * as serverBuildModule from '../../src/server/serverBuild';
 
 vi.mock('@sentry/core', async () => {
   const actual = await vi.importActual('@sentry/core');
@@ -22,6 +24,25 @@ vi.mock('@sentry/core', async () => {
   };
 });
 
+vi.mock('../../src/server/serverBuild', () => ({
+  getMiddlewareName: vi.fn(),
+}));
+
+vi.mock('@opentelemetry/api', async () => {
+  const actual = await vi.importActual('@opentelemetry/api');
+  return {
+    ...actual,
+    context: {
+      active: vi.fn(() => ({
+        getValue: vi.fn(),
+        setValue: vi.fn(),
+      })),
+      with: vi.fn((ctx, fn) => fn()),
+    },
+    createContextKey: actual.createContextKey,
+  };
+});
+
 describe('createSentryServerInstrumentation', () => {
   beforeEach(() => {
     vi.clearAllMocks();
@@ -287,12 +308,15 @@ describe('createSentryServerInstrumentation', () => {
     );
   });
 
-  it('should instrument route middleware with spans', async () => {
+  it('should instrument route middleware with spans (without function name)', async () => {
     const mockCallMiddleware = vi.fn().mockResolvedValue({ status: 'success', error: undefined });
     const mockInstrument = vi.fn();
     const mockSetAttributes = vi.fn();
     const mockRootSpan = { setAttributes: mockSetAttributes };
 
+    // No middleware name available
+    vi.mocked(serverBuildModule.getMiddlewareName).mockReturnValue(undefined);
+
     (core.startSpan as any).mockImplementation((_opts: any, fn: any) => fn());
     (core.getActiveSpan as any).mockReturnValue({});
     (core.getRootSpan as any).mockReturnValue(mockRootSpan);
@@ -317,17 +341,18 @@ describe('createSentryServerInstrumentation', () => {
 
     expect(core.startSpan).toHaveBeenCalledWith(
       expect.objectContaining({
-        name: '/users/:id',
+        name: 'middleware test-route',
         attributes: expect.objectContaining({
           'sentry.op': 'function.react_router.middleware',
           'sentry.origin': 'auto.function.react_router.instrumentation_api',
+          'react_router.route.id': 'test-route',
+          'react_router.route.pattern': '/users/:id',
+          'react_router.middleware.index': 0,
         }),
       }),
       expect.any(Function),
     );
 
-    // Verify updateRootSpanWithRoute was called (same as loader/action)
-    // This updates the root span name and sets http.route for parameterized routes
     expect(core.updateSpanName).toHaveBeenCalledWith(mockRootSpan, 'GET /users/:id');
     expect(mockSetAttributes).toHaveBeenCalledWith(
       expect.objectContaining({
@@ -337,6 +362,153 @@ describe('createSentryServerInstrumentation', () => {
     );
   });
 
+  it('should include middleware index attribute when tracking is available', async () => {
+    const mockCallMiddleware = vi.fn().mockResolvedValue({ status: 'success', error: undefined });
+    const mockInstrument = vi.fn();
+    const mockSetAttributes = vi.fn();
+    const mockRootSpan = { setAttributes: mockSetAttributes };
+    const routeId = 'routes/users-with-middleware';
+
+    vi.mocked(serverBuildModule.getMiddlewareName).mockReturnValue(undefined);
+
+    (core.startSpan as any).mockImplementation((_opts: any, fn: any) => fn());
+    (core.getActiveSpan as any).mockReturnValue({});
+    (core.getRootSpan as any).mockReturnValue(mockRootSpan);
+
+    const instrumentation = createSentryServerInstrumentation();
+    instrumentation.route?.({
+      id: routeId,
+      index: false,
+      path: '/users/:id',
+      instrument: mockInstrument,
+    });
+
+    const hooks = mockInstrument.mock.calls[0]![0];
+
+    await hooks.middleware(mockCallMiddleware, {
+      request: { method: 'GET', url: 'http://example.com/users/123', headers: { get: () => null } },
+      params: { id: '123' },
+      unstable_pattern: '/users/:id',
+      context: undefined,
+    });
+
+    expect(core.startSpan).toHaveBeenCalledWith(
+      expect.objectContaining({
+        name: `middleware ${routeId}`,
+        attributes: expect.objectContaining({
+          'sentry.op': 'function.react_router.middleware',
+          'react_router.route.id': routeId,
+          'react_router.route.pattern': '/users/:id',
+          'react_router.middleware.index': 0,
+        }),
+      }),
+      expect.any(Function),
+    );
+  });
+
+  it('should use middleware function name when available from serverBuild', async () => {
+    const mockCallMiddleware = vi.fn().mockResolvedValue({ status: 'success', error: undefined });
+    const mockInstrument = vi.fn();
+    const mockSetAttributes = vi.fn();
+    const mockRootSpan = { setAttributes: mockSetAttributes };
+    const routeId = 'routes/protected';
+
+    vi.mocked(serverBuildModule.getMiddlewareName).mockReturnValue('authMiddleware');
+
+    (core.startSpan as any).mockImplementation((_opts: any, fn: any) => fn());
+    (core.getActiveSpan as any).mockReturnValue({});
+    (core.getRootSpan as any).mockReturnValue(mockRootSpan);
+
+    const instrumentation = createSentryServerInstrumentation();
+    instrumentation.route?.({
+      id: routeId,
+      index: false,
+      path: '/protected',
+      instrument: mockInstrument,
+    });
+
+    const hooks = mockInstrument.mock.calls[0]![0];
+
+    await hooks.middleware(mockCallMiddleware, {
+      request: { method: 'GET', url: 'http://example.com/protected', headers: { get: () => null } },
+      params: {},
+      unstable_pattern: '/protected',
+      context: undefined,
+    });
+
+    expect(core.startSpan).toHaveBeenCalledWith(
+      expect.objectContaining({
+        name: 'middleware authMiddleware',
+        attributes: expect.objectContaining({
+          'sentry.op': 'function.react_router.middleware',
+          'react_router.route.id': routeId,
+          'react_router.route.pattern': '/protected',
+          'react_router.middleware.name': 'authMiddleware',
+          'react_router.middleware.index': 0,
+        }),
+      }),
+      expect.any(Function),
+    );
+  });
+
+  it('should increment middleware index for multiple middleware calls in same request via OTel context', async () => {
+    const mockCallMiddleware = vi.fn().mockResolvedValue({ status: 'success', error: undefined });
+    const mockInstrument = vi.fn();
+    const mockSetAttributes = vi.fn();
+    const mockRootSpan = { setAttributes: mockSetAttributes };
+    const routeId = 'routes/multi-middleware';
+
+    // Simulate counter store that would be created by handler and stored in OTel context
+    const counterStore = { counters: {} as Record<string, number> };
+
+    // eslint-disable-next-line @typescript-eslint/unbound-method
+    vi.mocked(otelApi.context.active).mockReturnValue({
+      getValue: vi.fn(() => counterStore),
+      setValue: vi.fn(),
+    } as any);
+
+    vi.mocked(serverBuildModule.getMiddlewareName).mockReturnValue(undefined);
+
+    const startSpanCalls: any[] = [];
+    (core.startSpan as any).mockImplementation((opts: any, fn: any) => {
+      startSpanCalls.push(opts);
+      return fn();
+    });
+    (core.getActiveSpan as any).mockReturnValue({});
+    (core.getRootSpan as any).mockReturnValue(mockRootSpan);
+
+    const instrumentation = createSentryServerInstrumentation();
+    instrumentation.route?.({
+      id: routeId,
+      index: false,
+      path: '/multi-middleware',
+      instrument: mockInstrument,
+    });
+
+    const hooks = mockInstrument.mock.calls[0]![0];
+    const requestInfo = {
+      request: { method: 'GET', url: 'http://example.com/multi-middleware', headers: { get: () => null } },
+      params: {},
+      unstable_pattern: '/multi-middleware',
+      context: undefined,
+    };
+
+    // Call middleware 3 times (simulating 3 middlewares on same route)
+    await hooks.middleware(mockCallMiddleware, requestInfo);
+    await hooks.middleware(mockCallMiddleware, requestInfo);
+    await hooks.middleware(mockCallMiddleware, requestInfo);
+
+    // Filter to only middleware spans
+    const middlewareSpans = startSpanCalls.filter(
+      opts => opts.attributes?.['sentry.op'] === 'function.react_router.middleware',
+    );
+
+    expect(middlewareSpans).toHaveLength(3);
+    expect(middlewareSpans[0].attributes['react_router.middleware.index']).toBe(0);
+    expect(middlewareSpans[1].attributes['react_router.middleware.index']).toBe(1);
+    expect(middlewareSpans[2].attributes['react_router.middleware.index']).toBe(2);
+  });
+
   it('should instrument lazy route loading with spans', async () => {
     const mockCallLazy = vi.fn().mockResolvedValue({ status: 'success', error: undefined });
     const mockInstrument = vi.fn();
diff --git a/packages/react-router/test/server/integration/reactRouterServer.test.ts b/packages/react-router/test/server/integration/reactRouterServer.test.ts
index a5eac42643e5..53a66b71fb90 100644
--- a/packages/react-router/test/server/integration/reactRouterServer.test.ts
+++ b/packages/react-router/test/server/integration/reactRouterServer.test.ts
@@ -1,4 +1,4 @@
-import * as SentryNode from '@sentry/node';
+import type { Event } from '@sentry/core';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 import { ReactRouterInstrumentation } from '../../../src/server/instrumentation/reactRouter';
 import { reactRouterServerIntegration } from '../../../src/server/integration/reactRouterServer';
@@ -14,11 +14,6 @@ vi.mock('@sentry/node', () => {
     generateInstrumentOnce: vi.fn((_name: string, callback: () => any) => {
       return Object.assign(callback, { id: 'test' });
     }),
-    NODE_VERSION: {
-      major: 0,
-      minor: 0,
-      patch: 0,
-    },
   };
 });
 
@@ -27,39 +22,79 @@ describe('reactRouterServerIntegration', () => {
     vi.clearAllMocks();
   });
 
-  it('sets up ReactRouterInstrumentation for Node 20.18', () => {
-    vi.spyOn(SentryNode, 'NODE_VERSION', 'get').mockReturnValue({ major: 20, minor: 18, patch: 0 });
-
+  it('sets up ReactRouterInstrumentation on setupOnce', () => {
     const integration = reactRouterServerIntegration();
     integration.setupOnce!();
 
     expect(ReactRouterInstrumentation).toHaveBeenCalled();
   });
 
-  it('sets up ReactRouterInstrumentationfor Node.js 22.11', () => {
-    vi.spyOn(SentryNode, 'NODE_VERSION', 'get').mockReturnValue({ major: 22, minor: 11, patch: 0 });
-
+  it('always sets up ReactRouterInstrumentation to capture ServerBuild for middleware name resolution', () => {
+    // The instrumentation is always installed to capture the ServerBuild reference,
+    // which is needed for middleware name resolution. The OTEL wrapper internally
+    // skips creating loader/action spans when the instrumentation API is active.
     const integration = reactRouterServerIntegration();
     integration.setupOnce!();
 
-    expect(ReactRouterInstrumentation).toHaveBeenCalled();
+    expect(ReactRouterInstrumentation).toHaveBeenCalledTimes(1);
   });
 
-  it('does not set up ReactRouterInstrumentation for Node.js 20.19', () => {
-    vi.spyOn(SentryNode, 'NODE_VERSION', 'get').mockReturnValue({ major: 20, minor: 19, patch: 0 });
-
+  it('has processEvent that removes bogus http.route attribute', () => {
     const integration = reactRouterServerIntegration();
-    integration.setupOnce!();
 
-    expect(ReactRouterInstrumentation).not.toHaveBeenCalled();
-  });
+    // Test with bogus * route and non-* transaction name
+    const event1 = {
+      type: 'transaction' as const,
+      contexts: {
+        trace: {
+          span_id: 'test-span-id',
+          trace_id: 'test-trace-id',
+          data: {
+            'http.route': '*',
+          },
+        },
+      },
+      transaction: 'GET /users',
+    } as Event;
 
-  it('does not set up ReactRouterInstrumentation for Node.js 22.12', () => {
-    vi.spyOn(SentryNode, 'NODE_VERSION', 'get').mockReturnValue({ major: 22, minor: 12, patch: 0 });
+    const result1 = integration.processEvent!(event1, {}, {} as any) as Event | null;
+    expect(result1?.contexts?.trace?.data?.['http.route']).toBeUndefined();
 
-    const integration = reactRouterServerIntegration();
-    integration.setupOnce!();
+    // Test with bogus * route but GET * transaction name (should keep)
+    const event2 = {
+      type: 'transaction' as const,
+      contexts: {
+        trace: {
+          span_id: 'test-span-id',
+          trace_id: 'test-trace-id',
+          data: {
+            'http.route': '*',
+          },
+        },
+      },
+      transaction: 'GET *',
+    } as Event;
+
+    const result2 = integration.processEvent!(event2, {}, {} as any) as Event | null;
+    expect(result2?.contexts?.trace?.data?.['http.route']).toBe('*');
+
+    // Test with instrumentation_api origin (should always remove)
+    const event3 = {
+      type: 'transaction' as const,
+      contexts: {
+        trace: {
+          span_id: 'test-span-id',
+          trace_id: 'test-trace-id',
+          origin: 'auto.http.react_router.instrumentation_api',
+          data: {
+            'http.route': '*',
+          },
+        },
+      },
+      transaction: 'GET *',
+    } as Event;
 
-    expect(ReactRouterInstrumentation).not.toHaveBeenCalled();
+    const result3 = integration.processEvent!(event3, {}, {} as any) as Event | null;
+    expect(result3?.contexts?.trace?.data?.['http.route']).toBeUndefined();
   });
 });
diff --git a/packages/react-router/test/server/serverBuild.test.ts b/packages/react-router/test/server/serverBuild.test.ts
new file mode 100644
index 000000000000..ec95953d5b5e
--- /dev/null
+++ b/packages/react-router/test/server/serverBuild.test.ts
@@ -0,0 +1,188 @@
+import { afterEach, describe, expect, it } from 'vitest';
+import { _resetServerBuild, getMiddlewareName, isServerBuildLike, setServerBuild } from '../../src/server/serverBuild';
+
+describe('serverBuild', () => {
+  afterEach(() => {
+    _resetServerBuild();
+  });
+
+  describe('setServerBuild', () => {
+    it('should store the build reference', () => {
+      const mockBuild = {
+        routes: {
+          'test-route': {
+            id: 'test-route',
+            module: {
+              middleware: [{ name: 'testMiddleware' }],
+            },
+          },
+        },
+      };
+
+      setServerBuild(mockBuild);
+
+      expect(getMiddlewareName('test-route', 0)).toBe('testMiddleware');
+    });
+  });
+
+  describe('getMiddlewareName', () => {
+    it('should return undefined when no build is stored', () => {
+      expect(getMiddlewareName('any-route', 0)).toBeUndefined();
+    });
+
+    it('should return undefined when routes is undefined', () => {
+      setServerBuild({});
+      expect(getMiddlewareName('test-route', 0)).toBeUndefined();
+    });
+
+    it('should return undefined when route does not exist', () => {
+      setServerBuild({
+        routes: {
+          'other-route': { module: { middleware: [{ name: 'test' }] } },
+        },
+      });
+
+      expect(getMiddlewareName('non-existent-route', 0)).toBeUndefined();
+    });
+
+    it('should return undefined when route has no module', () => {
+      setServerBuild({
+        routes: {
+          'test-route': {},
+        },
+      });
+
+      expect(getMiddlewareName('test-route', 0)).toBeUndefined();
+    });
+
+    it('should return undefined when module has no middleware', () => {
+      setServerBuild({
+        routes: {
+          'test-route': { module: {} },
+        },
+      });
+
+      expect(getMiddlewareName('test-route', 0)).toBeUndefined();
+    });
+
+    it('should return undefined when middleware array is empty', () => {
+      setServerBuild({
+        routes: {
+          'test-route': { module: { middleware: [] } },
+        },
+      });
+
+      expect(getMiddlewareName('test-route', 0)).toBeUndefined();
+    });
+
+    it('should return undefined when index is out of bounds', () => {
+      setServerBuild({
+        routes: {
+          'test-route': { module: { middleware: [{ name: 'first' }] } },
+        },
+      });
+
+      expect(getMiddlewareName('test-route', 1)).toBeUndefined();
+    });
+
+    it('should return undefined when middleware function has no name', () => {
+      setServerBuild({
+        routes: {
+          'test-route': { module: { middleware: [{}] } },
+        },
+      });
+
+      expect(getMiddlewareName('test-route', 0)).toBeUndefined();
+    });
+
+    it('should return undefined when middleware function name is empty string', () => {
+      setServerBuild({
+        routes: {
+          'test-route': { module: { middleware: [{ name: '' }] } },
+        },
+      });
+
+      expect(getMiddlewareName('test-route', 0)).toBeUndefined();
+    });
+
+    it('should return the middleware function name', () => {
+      setServerBuild({
+        routes: {
+          'test-route': {
+            module: {
+              middleware: [{ name: 'authMiddleware' }, { name: 'loggingMiddleware' }],
+            },
+          },
+        },
+      });
+
+      expect(getMiddlewareName('test-route', 0)).toBe('authMiddleware');
+      expect(getMiddlewareName('test-route', 1)).toBe('loggingMiddleware');
+    });
+
+    it('should work with multiple routes', () => {
+      setServerBuild({
+        routes: {
+          'route-a': { module: { middleware: [{ name: 'middlewareA' }] } },
+          'route-b': { module: { middleware: [{ name: 'middlewareB' }] } },
+        },
+      });
+
+      expect(getMiddlewareName('route-a', 0)).toBe('middlewareA');
+      expect(getMiddlewareName('route-b', 0)).toBe('middlewareB');
+    });
+  });
+
+  describe('_resetServerBuild', () => {
+    it('should clear the stored build reference', () => {
+      setServerBuild({
+        routes: {
+          'test-route': { module: { middleware: [{ name: 'test' }] } },
+        },
+      });
+
+      expect(getMiddlewareName('test-route', 0)).toBe('test');
+
+      _resetServerBuild();
+
+      expect(getMiddlewareName('test-route', 0)).toBeUndefined();
+    });
+  });
+
+  describe('isServerBuildLike', () => {
+    it('should return true for objects with routes property', () => {
+      expect(isServerBuildLike({ routes: {} })).toBe(true);
+      expect(isServerBuildLike({ routes: { 'test-route': {} } })).toBe(true);
+    });
+
+    it('should return false for null', () => {
+      expect(isServerBuildLike(null)).toBe(false);
+    });
+
+    it('should return false for undefined', () => {
+      expect(isServerBuildLike(undefined)).toBe(false);
+    });
+
+    it('should return false for primitives', () => {
+      expect(isServerBuildLike('string')).toBe(false);
+      expect(isServerBuildLike(123)).toBe(false);
+      expect(isServerBuildLike(true)).toBe(false);
+    });
+
+    it('should return false for objects without routes property', () => {
+      expect(isServerBuildLike({})).toBe(false);
+      expect(isServerBuildLike({ other: 'property' })).toBe(false);
+    });
+
+    it('should return false when routes is not an object', () => {
+      expect(isServerBuildLike({ routes: 'string' })).toBe(false);
+      expect(isServerBuildLike({ routes: 123 })).toBe(false);
+      expect(isServerBuildLike({ routes: null })).toBe(false);
+    });
+
+    it('should return false for arrays', () => {
+      expect(isServerBuildLike([])).toBe(false);
+      expect(isServerBuildLike([{ routes: {} }])).toBe(false);
+    });
+  });
+});