diff --git a/dev-packages/e2e-tests/test-applications/effect-3-browser/tests/transactions.test.ts b/dev-packages/e2e-tests/test-applications/effect-3-browser/tests/transactions.test.ts
index 331cb8b599e9..b2dfd2de9b54 100644
--- a/dev-packages/e2e-tests/test-applications/effect-3-browser/tests/transactions.test.ts
+++ b/dev-packages/e2e-tests/test-applications/effect-3-browser/tests/transactions.test.ts
@@ -75,4 +75,6 @@ test('captures Effect spans with correct parent-child structure', async ({ page
   expect(parentSpan).toBeDefined();
   expect(nestedSpan).toBeDefined();
   expect(nestedSpan?.parent_span_id).toBe(parentSpan?.span_id);
+  expect(parentSpan?.attributes['code.function.name']?.value).toBe('custom-effect-span');
+  expect(nestedSpan?.attributes['code.function.name']?.value).toBe('nested-span');
 });
diff --git a/dev-packages/e2e-tests/test-applications/effect-3-node/tests/spans.test.ts b/dev-packages/e2e-tests/test-applications/effect-3-node/tests/spans.test.ts
index 3b04189aea2f..6731b12f2ecf 100644
--- a/dev-packages/e2e-tests/test-applications/effect-3-node/tests/spans.test.ts
+++ b/dev-packages/e2e-tests/test-applications/effect-3-node/tests/spans.test.ts
@@ -52,6 +52,8 @@ test('Sends Effect spans with correct parent-child structure', async ({ baseURL
   expect(segment.name).toBe('http.server GET');
   expect(segment.attributes['sentry.origin']?.value).toBe('auto.http.effect');
   expect(segment.attributes['sentry.sdk.name']?.value).toBe('sentry.javascript.effect');
+  // `http.server` spans carry the route in their name, so they get no `code.function.name`.
+  expect(segment.attributes['code.function.name']).toBeUndefined();
   expect(children).toHaveLength(2);
   const parent = children.find(span => span.name === 'custom-effect-span')!;
   const nested = children.find(span => span.name === 'nested-span')!;
@@ -60,6 +62,7 @@ test('Sends Effect spans with correct parent-child structure', async ({ baseURL
   for (const child of children) {
     expect(getSpanOp(child)).toBe('function');
     expect(child.attributes['sentry.origin']?.value).toBe('auto.function.effect');
+    expect(child.attributes['code.function.name']?.value).toBe(child.name);
     expect(child.trace_id).toBe(segment.trace_id);
   }
 });
diff --git a/dev-packages/e2e-tests/test-applications/effect-4-browser/tests/transactions.test.ts b/dev-packages/e2e-tests/test-applications/effect-4-browser/tests/transactions.test.ts
index 971f5678c276..1d0335798d1c 100644
--- a/dev-packages/e2e-tests/test-applications/effect-4-browser/tests/transactions.test.ts
+++ b/dev-packages/e2e-tests/test-applications/effect-4-browser/tests/transactions.test.ts
@@ -75,4 +75,6 @@ test('captures Effect spans with correct parent-child structure', async ({ page
   expect(parentSpan).toBeDefined();
   expect(nestedSpan).toBeDefined();
   expect(nestedSpan?.parent_span_id).toBe(parentSpan?.span_id);
+  expect(parentSpan?.attributes['code.function.name']?.value).toBe('custom-effect-span');
+  expect(nestedSpan?.attributes['code.function.name']?.value).toBe('nested-span');
 });
diff --git a/dev-packages/e2e-tests/test-applications/effect-4-node/tests/spans.test.ts b/dev-packages/e2e-tests/test-applications/effect-4-node/tests/spans.test.ts
index 7477d91a04be..f1b1ce5ae36e 100644
--- a/dev-packages/e2e-tests/test-applications/effect-4-node/tests/spans.test.ts
+++ b/dev-packages/e2e-tests/test-applications/effect-4-node/tests/spans.test.ts
@@ -52,6 +52,8 @@ test('Sends Effect spans with correct parent-child structure', async ({ baseURL
   expect(segment.name).toBe('http.server GET');
   expect(segment.attributes['sentry.origin']?.value).toBe('auto.http.effect');
   expect(segment.attributes['sentry.sdk.name']?.value).toBe('sentry.javascript.effect');
+  // `http.server` spans carry the route in their name, so they get no `code.function.name`.
+  expect(segment.attributes['code.function.name']).toBeUndefined();
   expect(children).toHaveLength(2);
   const parent = children.find(span => span.name === 'custom-effect-span')!;
   const nested = children.find(span => span.name === 'nested-span')!;
@@ -60,6 +62,7 @@ test('Sends Effect spans with correct parent-child structure', async ({ baseURL
   for (const child of children) {
     expect(getSpanOp(child)).toBe('function');
     expect(child.attributes['sentry.origin']?.value).toBe('auto.function.effect');
+    expect(child.attributes['code.function.name']?.value).toBe(child.name);
     expect(child.trace_id).toBe(segment.trace_id);
   }
 });
diff --git a/packages/effect/src/tracer.ts b/packages/effect/src/tracer.ts
index 31ac0be35c29..cc65c44d9101 100644
--- a/packages/effect/src/tracer.ts
+++ b/packages/effect/src/tracer.ts
@@ -1,4 +1,4 @@
-import { SENTRY_OP } from '@sentry/conventions/attributes';
+import { CODE_FUNCTION_NAME, SENTRY_OP } from '@sentry/conventions/attributes';
 import { FUNCTION, HTTP_CLIENT, HTTP_SERVER } from '@sentry/conventions/op';
 import type { Span, StartSpanOptions } from '@sentry/core';
 import { isObjectLike, getActiveSpan, SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN, withActiveSpan } from '@sentry/core';
@@ -190,12 +190,15 @@ function createSentrySpan(
   const parentSentrySpan =
     Option.isSome(parent) && isSentrySpan(parent.value) ? parent.value.sentrySpan : (getActiveSpan() ?? null);
 
+  const op = deriveOp(name);
+
   const newSpan = startInactiveSpan({
     name,
     startTime: nanosToHrTime(startTime),
     attributes: {
-      [SENTRY_OP]: deriveOp(name),
+      [SENTRY_OP]: op,
       [SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: deriveOrigin(name),
+      ...(op === FUNCTION && { [CODE_FUNCTION_NAME]: name }),
     },
     ...(parentSentrySpan ? { parentSpan: parentSentrySpan } : {}),
   });
diff --git a/packages/effect/test/tracer.test.ts b/packages/effect/test/tracer.test.ts
index a056227576e1..91aae81ca918 100644
--- a/packages/effect/test/tracer.test.ts
+++ b/packages/effect/test/tracer.test.ts
@@ -1,6 +1,7 @@
 import { describe, expect, it } from '@effect/vitest';
 import * as sentryCore from '@sentry/core';
 import * as sentryCoreBrowser from '@sentry/core/browser';
+import { CODE_FUNCTION_NAME } from '@sentry/conventions/attributes';
 import { SEMANTIC_ATTRIBUTE_SENTRY_OP, SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN } from '@sentry/core';
 import { Effect } from 'effect';
 import { afterEach, vi } from 'vitest';
@@ -198,6 +199,7 @@ describe.each(VARIANTS)('SentryEffectTracer ($variant)', ({ tracer, spanApi }) =
 
       expect(attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]).toBe('auto.function.effect');
       expect(attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_OP]).toBe('function');
+      expect(attributes?.[CODE_FUNCTION_NAME]).toBe('my-operation');
     }),
   );
 
@@ -207,6 +209,7 @@ describe.each(VARIANTS)('SentryEffectTracer ($variant)', ({ tracer, spanApi }) =
 
       expect(attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]).toBe('auto.http.effect');
       expect(attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_OP]).toBe('http.server');
+      expect(attributes?.[CODE_FUNCTION_NAME]).toBeUndefined();
     }),
   );
 
@@ -216,6 +219,7 @@ describe.each(VARIANTS)('SentryEffectTracer ($variant)', ({ tracer, spanApi }) =
 
       expect(attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]).toBe('auto.http.effect');
       expect(attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_OP]).toBe('http.client');
+      expect(attributes?.[CODE_FUNCTION_NAME]).toBeUndefined();
     }),
   );