diff --git a/dev-packages/cloudflare-integration-tests/suites/hono-sdk/test.ts b/dev-packages/cloudflare-integration-tests/suites/hono-sdk/test.ts
index 33ba266ed7cc..91baf7ea70b7 100644
--- a/dev-packages/cloudflare-integration-tests/suites/hono-sdk/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/hono-sdk/test.ts
@@ -1,5 +1,5 @@
 import { expect, it } from 'vitest';
-import { eventEnvelope } from '../../expect';
+import { eventEnvelope, SHORT_UUID_MATCHER, UUID_MATCHER } from '../../expect';
 import { createRunner } from '../../runner';
 import { getSpanOp, getSpansFromEnvelope } from '../../spanUtils';
 
@@ -28,6 +28,11 @@ it('Hono app captures parametrized errors (Hono SDK)', async ({ signal }) => {
             method: 'GET',
             url: expect.stringContaining('/error/param-123'),
           },
+          contexts: {
+            // On runtimes with `Span.spanContext()`, the span continues the Cloudflare trace, so the trace context also
+            // has the Cloudflare span as `parent_span_id`.
+            trace: expect.objectContaining({ trace_id: UUID_MATCHER, span_id: SHORT_UUID_MATCHER }),
+          },
           breadcrumbs: [
             {
               timestamp: expect.any(Number),
diff --git a/dev-packages/cloudflare-integration-tests/suites/public-api/startSpan/test.ts b/dev-packages/cloudflare-integration-tests/suites/public-api/startSpan/test.ts
index 0fa5d410368b..477de95533ee 100644
--- a/dev-packages/cloudflare-integration-tests/suites/public-api/startSpan/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/public-api/startSpan/test.ts
@@ -183,7 +183,11 @@ it('sends a streamed span envelope with correct spans for a manually started spa
     status: 'ok',
   });
 
-  expect(segmentSpan).toEqual({
+  // On runtimes with `Span.spanContext()`, the segment continues the Cloudflare trace, so the Cloudflare span is its parent.
+  const { parent_span_id: segmentParentSpanId, ...segmentSpanWithoutParent } = segmentSpan!;
+  expect(segmentParentSpanId).toBeOneOf([undefined, expect.stringMatching(/^[\da-f]{16}$/)]);
+
+  expect(segmentSpanWithoutParent).toEqual({
     attributes: {
       'sentry.is_localhost': { value: true, type: 'boolean' },
       [SENTRY_TRACE_LIFECYCLE]: { type: 'string', value: 'stream' },
diff --git a/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/index.ts b/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/index.ts
new file mode 100644
index 000000000000..7be3482cf480
--- /dev/null
+++ b/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/index.ts
@@ -0,0 +1,18 @@
+import * as Sentry from '@sentry/cloudflare';
+
+// `getActiveSpan` and `Span.spanContext` are newer than the installed workers types, and older runtimes do not have
+// them.
+interface CloudflareTracing {
+  getActiveSpan?(): { isTraced?: boolean; spanContext?(): { traceId: string; spanId: string } } | undefined;
+}
+
+export default {
+  async fetch(_request, _env, ctx) {
+    const span = (ctx.tracing as unknown as CloudflareTracing | undefined)?.getActiveSpan?.();
+    const cloudflareSpan = span?.isTraced ? (span.spanContext?.() ?? null) : null;
+
+    Sentry.captureException(new Error('Error in a Cloudflare trace'));
+
+    return Response.json(cloudflareSpan);
+  },
+} satisfies ExportedHandler;
diff --git a/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/instrument.server.ts b/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/instrument.server.ts
new file mode 100644
index 000000000000..c38c68786a23
--- /dev/null
+++ b/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/instrument.server.ts
@@ -0,0 +1,6 @@
+import { defineCloudflareOptions } from '@sentry/cloudflare';
+
+export default defineCloudflareOptions((env: { SENTRY_DSN: string; TRACES_SAMPLE_RATE: string }) => ({
+  dsn: env.SENTRY_DSN,
+  tracesSampleRate: Number(env.TRACES_SAMPLE_RATE),
+}));
diff --git a/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/test.ts b/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/test.ts
new file mode 100644
index 000000000000..2d7a2502080b
--- /dev/null
+++ b/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/test.ts
@@ -0,0 +1,96 @@
+import type { Event, SerializedStreamedSpanContainer } from '@sentry/core';
+import { createRequire } from 'module';
+import { expect, it } from 'vitest';
+import { SHORT_UUID_MATCHER } from '../../../expect';
+import { createRunner } from '../../../runner';
+
+// `wrangler dev` runs the workerd of its own miniflare. `Span.spanContext()` ships in workerd 1.20261009.1, so the
+// pinned wrangler runs these tests without it and the latest wrangler runs them with it.
+const wranglerRequire = createRequire(createRequire(__filename).resolve('wrangler/package.json'));
+const miniflareRequire = createRequire(wranglerRequire.resolve('miniflare/package.json'));
+const [, workerdDate = 0, workerdPatch = 0] = (miniflareRequire('workerd/package.json') as { version: string }).version
+  .split('.')
+  .map(Number);
+const HAS_SPAN_CONTEXT = workerdDate > 20261009 || (workerdDate === 20261009 && workerdPatch >= 1);
+
+const VALID_TRACE_ID = expect.stringMatching(/^(?!0{32})[\da-f]{32}$/);
+// Without `Span.spanContext()`, the Worker responds with `null` and the SDK starts its own trace. On a runtime with it,
+// a `null` response fails the test, so the `VALID_TRACE_ID` fallbacks below apply only to older runtimes.
+const EXPECTED_CLOUDFLARE_SPAN = HAS_SPAN_CONTEXT
+  ? expect.objectContaining({ traceId: VALID_TRACE_ID, spanId: SHORT_UUID_MATCHER })
+  : null;
+
+it('uses the Cloudflare trace for the error event and the segment span', async ({ signal }) => {
+  const errorEvents: Event[] = [];
+  const spanContainers: SerializedStreamedSpanContainer[] = [];
+
+  const runner = createRunner(__dirname)
+    .unordered()
+    .expect(envelope => {
+      expect(envelope[1][0][0].type).toBe('event');
+      errorEvents.push(envelope[1][0][1] as Event);
+    })
+    .expect(envelope => {
+      expect(envelope[1][0][0].type).toBe('span');
+      spanContainers.push(envelope[1][0][1] as SerializedStreamedSpanContainer);
+    })
+    .start(signal);
+
+  const cloudflareSpan = await runner.makeRequest<{ traceId: string; spanId: string } | null>('get', '/');
+  await runner.completed();
+
+  const segmentSpans = spanContainers.flatMap(container => container.items).filter(span => span.is_segment);
+  expect(cloudflareSpan).toEqual(EXPECTED_CLOUDFLARE_SPAN);
+  expect(errorEvents).toHaveLength(1);
+  expect(segmentSpans).toHaveLength(1);
+  expect(segmentSpans[0]?.trace_id).toEqual(cloudflareSpan?.traceId ?? VALID_TRACE_ID);
+  expect(segmentSpans[0]?.parent_span_id).toBe(cloudflareSpan?.spanId);
+  expect(errorEvents[0]?.contexts?.trace?.trace_id).toBe(segmentSpans[0]?.trace_id);
+});
+
+it('uses the Cloudflare trace for the error event when no span is sampled', async ({ signal }) => {
+  const errorEvents: Event[] = [];
+
+  const runner = createRunner(__dirname)
+    .withWranglerArgs('--var', 'TRACES_SAMPLE_RATE:0')
+    .expect(envelope => {
+      expect(envelope[1][0][0].type).toBe('event');
+      errorEvents.push(envelope[1][0][1] as Event);
+    })
+    .start(signal);
+
+  const cloudflareSpan = await runner.makeRequest<{ traceId: string; spanId: string } | null>('get', '/');
+  await runner.completed();
+
+  expect(cloudflareSpan).toEqual(EXPECTED_CLOUDFLARE_SPAN);
+  expect(errorEvents).toHaveLength(1);
+  expect(errorEvents[0]?.contexts?.trace).toEqual({
+    trace_id: cloudflareSpan?.traceId ?? VALID_TRACE_ID,
+    span_id: SHORT_UUID_MATCHER,
+    parent_span_id: cloudflareSpan?.spanId,
+  });
+});
+
+it('continues an incoming Sentry trace instead of the Cloudflare trace', async ({ signal }) => {
+  const errorEvents: Event[] = [];
+
+  const runner = createRunner(__dirname)
+    .unordered()
+    .expect(envelope => {
+      expect(envelope[1][0][0].type).toBe('event');
+      errorEvents.push(envelope[1][0][1] as Event);
+    })
+    .expect(envelope => {
+      expect(envelope[1][0][0].type).toBe('span');
+    })
+    .start(signal);
+
+  await runner.makeRequest('get', '/', {
+    headers: { 'sentry-trace': '12345678901234567890123456789012-1234567890123456-1' },
+  });
+  await runner.completed();
+
+  expect(errorEvents).toHaveLength(1);
+  expect(errorEvents[0]?.contexts?.trace?.trace_id).toBe('12345678901234567890123456789012');
+  expect(errorEvents[0]?.contexts?.trace?.parent_span_id).toBe('1234567890123456');
+});
diff --git a/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/vite.config.mts b/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/vite.config.mts
new file mode 100644
index 000000000000..005f4448f6cb
--- /dev/null
+++ b/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/vite.config.mts
@@ -0,0 +1,7 @@
+import { cloudflare } from '@cloudflare/vite-plugin';
+import { sentryCloudflareVitePlugin } from '@sentry/cloudflare/vite';
+import { defineConfig } from 'vite';
+
+export default defineConfig({
+  plugins: [cloudflare(), sentryCloudflareVitePlugin()],
+});
diff --git a/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/wrangler.jsonc b/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/wrangler.jsonc
new file mode 100644
index 000000000000..7edd747472d8
--- /dev/null
+++ b/dev-packages/cloudflare-integration-tests/suites/tracing/cloudflare-trace/wrangler.jsonc
@@ -0,0 +1,9 @@
+{
+  "name": "cloudflare-trace-worker",
+  "compatibility_date": "2025-06-17",
+  "main": "index.ts",
+  "compatibility_flags": ["nodejs_compat"],
+  "vars": {
+    "TRACES_SAMPLE_RATE": "1",
+  },
+}
diff --git a/dev-packages/cloudflare-integration-tests/suites/tracing/dsc-url-source/test.ts b/dev-packages/cloudflare-integration-tests/suites/tracing/dsc-url-source/test.ts
index f9916e5c03c7..c8c8506c1842 100644
--- a/dev-packages/cloudflare-integration-tests/suites/tracing/dsc-url-source/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/tracing/dsc-url-source/test.ts
@@ -1,5 +1,5 @@
 import { expect, it } from 'vitest';
-import { eventEnvelope } from '../../../expect';
+import { eventEnvelope, SHORT_UUID_MATCHER, UUID_MATCHER } from '../../../expect';
 import { createRunner } from '../../../runner';
 import { getSpanOp, getSpansFromEnvelope } from '../../../spanUtils';
 
@@ -29,6 +29,11 @@ it('omits the span name from the DSC for url-source spans when tracing is enable
             method: 'GET',
             url: expect.any(String),
           },
+          contexts: {
+            // On runtimes with `Span.spanContext()`, the span continues the Cloudflare trace, so the trace context also
+            // has the Cloudflare span as `parent_span_id`.
+            trace: expect.objectContaining({ trace_id: UUID_MATCHER, span_id: SHORT_UUID_MATCHER }),
+          },
         },
         { includeSamplingFields: true, includeSampleRand: true, includeTransaction: false },
       ),
diff --git a/dev-packages/cloudflare-integration-tests/suites/tracing/instrument-fetcher/test.ts b/dev-packages/cloudflare-integration-tests/suites/tracing/instrument-fetcher/test.ts
index 53a5651214b9..ec312ba550fd 100644
--- a/dev-packages/cloudflare-integration-tests/suites/tracing/instrument-fetcher/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/tracing/instrument-fetcher/test.ts
@@ -15,8 +15,7 @@ type EchoedHeaders = {
 const SENTRY_TRACE_HEADER_RE = /^[0-9a-f]{32}-[0-9a-f]{16}-[01]$/;
 
 function startStubFetchScenario(signal: AbortSignal) {
-  let mainSpan: SerializedStreamedSpan | undefined;
-  let doSpan: SerializedStreamedSpan | undefined;
+  const segmentSpans: SerializedStreamedSpan[] = [];
 
   // The worker and the Durable Object stream their spans from separate isolates, so each one
   // arrives in its own envelope.
@@ -25,15 +24,13 @@ function startStubFetchScenario(signal: AbortSignal) {
       const segmentSpan = getSpansFromEnvelope(envelope).find(span => span.is_segment);
 
       expect(getSpanOp(segmentSpan!)).toBe('http.server');
-      expect(segmentSpan?.parent_span_id).toBeUndefined();
-      mainSpan = segmentSpan;
+      segmentSpans.push(segmentSpan!);
     })
     .expect(envelope => {
       const segmentSpan = getSpansFromEnvelope(envelope).find(span => span.is_segment);
 
       expect(getSpanOp(segmentSpan!)).toBe('http.server');
-      expect(segmentSpan?.parent_span_id).toBeDefined();
-      doSpan = segmentSpan;
+      segmentSpans.push(segmentSpan!);
     })
     .unordered()
     .start(signal);
@@ -43,6 +40,10 @@ function startStubFetchScenario(signal: AbortSignal) {
     async completedWithTraceCheck(): Promise<void> {
       await completed();
 
+      // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+      const doSpan = segmentSpans.find(span => segmentSpans.some(parent => parent.span_id === span.parent_span_id));
+      const mainSpan = segmentSpans.find(span => span !== doSpan);
+
       // Both routes are raw URLs, so the streamed segment name keeps the method only.
       expect(mainSpan?.name).toBe('GET');
       expect(doSpan?.name).toBe('GET');
diff --git a/dev-packages/cloudflare-integration-tests/suites/tracing/propagation/worker-service-binding/test.ts b/dev-packages/cloudflare-integration-tests/suites/tracing/propagation/worker-service-binding/test.ts
index 6fd5fa551512..b66a6fe38aee 100644
--- a/dev-packages/cloudflare-integration-tests/suites/tracing/propagation/worker-service-binding/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/tracing/propagation/worker-service-binding/test.ts
@@ -14,8 +14,9 @@ it('propagates trace from worker to worker via service binding', async ({ signal
   await runner.makeRequest('get', '/');
 
   const segmentSpans = (await spansPromise).filter(span => span.is_segment);
-  const worker = segmentSpans.find(span => !span.parent_span_id);
-  const subWorker = segmentSpans.find(span => span.parent_span_id);
+  // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+  const subWorker = segmentSpans.find(span => segmentSpans.some(parent => parent.span_id === span.parent_span_id));
+  const worker = segmentSpans.find(span => span !== subWorker);
 
   expect(worker?.name).toBe('GET /');
   expect(worker?.attributes['sentry.origin']).toEqual({ type: 'string', value: 'auto.http.cloudflare' });
diff --git a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/combination-entrypoint-do-manual-mixed/test.ts b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/combination-entrypoint-do-manual-mixed/test.ts
index 1630042291f6..349a1f3f91c5 100644
--- a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/combination-entrypoint-do-manual-mixed/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/combination-entrypoint-do-manual-mixed/test.ts
@@ -49,8 +49,11 @@ it('leaves a manually wrapped Durable Object untouched while auto-wrapping a sib
   await runner.makeRequest('get', '/increment');
 
   const durableObjectTraceSpans = await durableObjectSpansPromise;
-  const workerSpan = durableObjectTraceSpans.find(span => span.is_segment && !span.parent_span_id);
-  const durableObjectSpan = durableObjectTraceSpans.find(span => span.is_segment && span.parent_span_id);
+  // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+  const durableObjectSpan = durableObjectTraceSpans.find(
+    span => span.is_segment && durableObjectTraceSpans.some(parent => parent.span_id === span.parent_span_id),
+  );
+  const workerSpan = durableObjectTraceSpans.find(span => span.is_segment && span !== durableObjectSpan);
 
   expect(getSpanOp(workerSpan!)).toBe('http.server');
   expect(getSpanOp(durableObjectSpan!)).toBe('http.server');
diff --git a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/combination-entrypoint-do/test.ts b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/combination-entrypoint-do/test.ts
index cf4768c16c01..dbe54655d7d6 100644
--- a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/combination-entrypoint-do/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/combination-entrypoint-do/test.ts
@@ -47,8 +47,11 @@ it('auto-instruments a WorkerEntrypoint and a Durable Object exported from the s
   await runner.makeRequest('get', '/increment');
 
   const durableObjectTraceSpans = await durableObjectSpansPromise;
-  const workerSpan = durableObjectTraceSpans.find(span => span.is_segment && !span.parent_span_id);
-  const durableObjectSpan = durableObjectTraceSpans.find(span => span.is_segment && span.parent_span_id);
+  // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+  const durableObjectSpan = durableObjectTraceSpans.find(
+    span => span.is_segment && durableObjectTraceSpans.some(parent => parent.span_id === span.parent_span_id),
+  );
+  const workerSpan = durableObjectTraceSpans.find(span => span.is_segment && span !== durableObjectSpan);
 
   expect(getSpanOp(workerSpan!)).toBe('http.server');
   expect(getSpanOp(durableObjectSpan!)).toBe('http.server');
diff --git a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-manual-wrap/test.ts b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-manual-wrap/test.ts
index e538a69912a9..df2d9926230c 100644
--- a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-manual-wrap/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-manual-wrap/test.ts
@@ -20,8 +20,11 @@ it('leaves a manually wrapped Durable Object untouched and still wraps the defau
   await runner.makeRequest('get', '/increment');
 
   const spans = await spansPromise;
-  const workerSpan = spans.find(span => span.is_segment && !span.parent_span_id);
-  const durableObjectSpan = spans.find(span => span.is_segment && span.parent_span_id);
+  // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+  const durableObjectSpan = spans.find(
+    span => span.is_segment && spans.some(parent => parent.span_id === span.parent_span_id),
+  );
+  const workerSpan = spans.find(span => span.is_segment && span !== durableObjectSpan);
 
   expect(getSpanOp(workerSpan!)).toBe('http.server');
   expect(workerSpan?.attributes['sentry.origin']).toEqual({ type: 'string', value: 'auto.http.cloudflare' });
diff --git a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-mixed/test.ts b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-mixed/test.ts
index 972039a27bda..eb2008e86da4 100644
--- a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-mixed/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-mixed/test.ts
@@ -21,8 +21,11 @@ it('wraps only the unwrapped Durable Object when a sibling is manually wrapped',
     await runner.makeRequest('get', path);
 
     const spans = await spansPromise;
-    const workerSpan = spans.find(span => span.is_segment && !span.parent_span_id);
-    const durableObjectSpan = spans.find(span => span.is_segment && span.parent_span_id);
+    // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+    const durableObjectSpan = spans.find(
+      span => span.is_segment && spans.some(parent => parent.span_id === span.parent_span_id),
+    );
+    const workerSpan = spans.find(span => span.is_segment && span !== durableObjectSpan);
 
     expect(getSpanOp(workerSpan!)).toBe('http.server');
     expect(workerSpan?.attributes['url.path']).toEqual({ type: 'string', value: path });
diff --git a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-multiple/test.ts b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-multiple/test.ts
index eaa634bf2073..bec562208e14 100644
--- a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-multiple/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-multiple/test.ts
@@ -19,8 +19,11 @@ it('auto-instruments multiple Durable Object classes in one entry', async ({ sig
     await runner.makeRequest('get', path);
 
     const spans = await spansPromise;
-    const workerSpan = spans.find(span => span.is_segment && !span.parent_span_id);
-    const durableObjectSpan = spans.find(span => span.is_segment && span.parent_span_id);
+    // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+    const durableObjectSpan = spans.find(
+      span => span.is_segment && spans.some(parent => parent.span_id === span.parent_span_id),
+    );
+    const workerSpan = spans.find(span => span.is_segment && span !== durableObjectSpan);
 
     expect(getSpanOp(workerSpan!)).toBe('http.server');
     expect(workerSpan?.attributes['url.path']).toEqual({ type: 'string', value: path });
diff --git a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-reexport-instrumented/test.ts b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-reexport-instrumented/test.ts
index 63d164ff5c84..04bda0f2c764 100644
--- a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-reexport-instrumented/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-reexport-instrumented/test.ts
@@ -24,8 +24,11 @@ it('does not double-instrument an imported, already-wrapped Durable Object and s
   await runner.makeRequest('get', '/increment');
 
   const spans = await spansPromise;
-  const workerSpan = spans.find(span => span.is_segment && !span.parent_span_id);
-  const durableObjectSpan = spans.find(span => span.is_segment && span.parent_span_id);
+  // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+  const durableObjectSpan = spans.find(
+    span => span.is_segment && spans.some(parent => parent.span_id === span.parent_span_id),
+  );
+  const workerSpan = spans.find(span => span.is_segment && span !== durableObjectSpan);
 
   expect(getSpanOp(workerSpan!)).toBe('http.server');
   expect(workerSpan?.attributes['sentry.origin']).toEqual({ type: 'string', value: 'auto.http.cloudflare' });
diff --git a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-specifier-alias/test.ts b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-specifier-alias/test.ts
index a54d5dfa0308..293da45171a3 100644
--- a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-specifier-alias/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-specifier-alias/test.ts
@@ -18,8 +18,11 @@ it('auto-instruments a Durable Object exported via an aliased specifier', async
   await runner.makeRequest('get', '/increment');
 
   const spans = await spansPromise;
-  const workerSpan = spans.find(span => span.is_segment && !span.parent_span_id);
-  const durableObjectSpan = spans.find(span => span.is_segment && span.parent_span_id);
+  // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+  const durableObjectSpan = spans.find(
+    span => span.is_segment && spans.some(parent => parent.span_id === span.parent_span_id),
+  );
+  const workerSpan = spans.find(span => span.is_segment && span !== durableObjectSpan);
 
   expect(getSpanOp(workerSpan!)).toBe('http.server');
   expect(workerSpan?.attributes['sentry.origin']).toEqual({ type: 'string', value: 'auto.http.cloudflare' });
diff --git a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-specifier/test.ts b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-specifier/test.ts
index 7b02c87d3df9..256f4766b891 100644
--- a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-specifier/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-specifier/test.ts
@@ -18,8 +18,11 @@ it('auto-instruments a Durable Object exported via a specifier list', async ({ s
   await runner.makeRequest('get', '/increment');
 
   const spans = await spansPromise;
-  const workerSpan = spans.find(span => span.is_segment && !span.parent_span_id);
-  const durableObjectSpan = spans.find(span => span.is_segment && span.parent_span_id);
+  // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+  const durableObjectSpan = spans.find(
+    span => span.is_segment && spans.some(parent => parent.span_id === span.parent_span_id),
+  );
+  const workerSpan = spans.find(span => span.is_segment && span !== durableObjectSpan);
 
   expect(getSpanOp(workerSpan!)).toBe('http.server');
   expect(workerSpan?.attributes['sentry.origin']).toEqual({ type: 'string', value: 'auto.http.cloudflare' });
diff --git a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-workflow-manual-mixed/test.ts b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-workflow-manual-mixed/test.ts
index 4abc814568d3..4bc8d855cfc2 100644
--- a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-workflow-manual-mixed/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-workflow-manual-mixed/test.ts
@@ -22,8 +22,11 @@ it('leaves a manually wrapped Durable Object untouched and still auto-wraps a Wo
   await runner.makeRequest('get', '/increment');
 
   const spans = await durableObjectSpansPromise;
-  const workerSpan = spans.find(span => span.is_segment && !span.parent_span_id);
-  const durableObjectSpan = spans.find(span => span.is_segment && span.parent_span_id);
+  // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+  const durableObjectSpan = spans.find(
+    span => span.is_segment && spans.some(parent => parent.span_id === span.parent_span_id),
+  );
+  const workerSpan = spans.find(span => span.is_segment && span !== durableObjectSpan);
 
   expect(getSpanOp(workerSpan!)).toBe('http.server');
   expect(workerSpan?.attributes['sentry.origin']).toEqual({ type: 'string', value: 'auto.http.cloudflare' });
diff --git a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-workflow-specifier/test.ts b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-workflow-specifier/test.ts
index ffefbcade6c3..d28ae9a14e7c 100644
--- a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-workflow-specifier/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-workflow-specifier/test.ts
@@ -21,8 +21,11 @@ it('auto-instruments a Durable Object and a Workflow exported via a specifier li
   await runner.makeRequest('get', '/increment');
 
   const spans = await durableObjectSpansPromise;
-  const workerSpan = spans.find(span => span.is_segment && !span.parent_span_id);
-  const durableObjectSpan = spans.find(span => span.is_segment && span.parent_span_id);
+  // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+  const durableObjectSpan = spans.find(
+    span => span.is_segment && spans.some(parent => parent.span_id === span.parent_span_id),
+  );
+  const workerSpan = spans.find(span => span.is_segment && span !== durableObjectSpan);
 
   expect(getSpanOp(workerSpan!)).toBe('http.server');
   expect(workerSpan?.attributes['sentry.origin']).toEqual({ type: 'string', value: 'auto.http.cloudflare' });
diff --git a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-workflow/test.ts b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-workflow/test.ts
index 9861748a30ce..8a159ac29206 100644
--- a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-workflow/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject-workflow/test.ts
@@ -20,8 +20,11 @@ it('auto-instruments a Durable Object and a Workflow in the same entry', async (
   await runner.makeRequest('get', '/increment');
 
   const spans = await durableObjectSpansPromise;
-  const workerSpan = spans.find(span => span.is_segment && !span.parent_span_id);
-  const durableObjectSpan = spans.find(span => span.is_segment && span.parent_span_id);
+  // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+  const durableObjectSpan = spans.find(
+    span => span.is_segment && spans.some(parent => parent.span_id === span.parent_span_id),
+  );
+  const workerSpan = spans.find(span => span.is_segment && span !== durableObjectSpan);
 
   expect(getSpanOp(workerSpan!)).toBe('http.server');
   expect(workerSpan?.attributes['sentry.origin']).toEqual({ type: 'string', value: 'auto.http.cloudflare' });
diff --git a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject/test.ts b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject/test.ts
index c7012293e240..be4a9e3ba6be 100644
--- a/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/vite-autoinstrument/durableobject/test.ts
@@ -26,8 +26,11 @@ it('auto-instruments the default handler and a Durable Object', async ({ signal
   await runner.makeRequest('get', '/increment');
 
   const spans = await spansPromise;
-  const workerSpan = spans.find(span => span.is_segment && !span.parent_span_id);
-  const durableObjectSpan = spans.find(span => span.is_segment && span.parent_span_id);
+  // The worker segment has no parent in this trace. On runtimes with `Span.spanContext()`, its parent is the Cloudflare span.
+  const durableObjectSpan = spans.find(
+    span => span.is_segment && spans.some(parent => parent.span_id === span.parent_span_id),
+  );
+  const workerSpan = spans.find(span => span.is_segment && span !== durableObjectSpan);
 
   expect(getSpanOp(workerSpan!)).toBe('http.server');
   expect(workerSpan?.attributes['sentry.origin']).toEqual({ type: 'string', value: 'auto.http.cloudflare' });
diff --git a/packages/cloudflare/src/instrumentations/worker/instrumentEmail.ts b/packages/cloudflare/src/instrumentations/worker/instrumentEmail.ts
index 11a8fb9b419d..cafb160e896b 100644
--- a/packages/cloudflare/src/instrumentations/worker/instrumentEmail.ts
+++ b/packages/cloudflare/src/instrumentations/worker/instrumentEmail.ts
@@ -16,6 +16,7 @@ import { ensureInstrumented } from '../../instrument';
 import { getFinalOptions } from '../../options';
 import { addCloudResourceContext } from '../../scope-utils';
 import { init } from '../../sdk';
+import { continueCloudflareTrace } from '../../utils/cloudflareTrace';
 import { instrumentContext } from '../../utils/instrumentContext';
 import { setInvocationState } from '../../utils/invocationContext';
 import { instrumentEnv } from './instrumentEnv';
@@ -38,6 +39,7 @@ function wrapEmailHandler(
     isolationScope.setClient(client);
 
     addCloudResourceContext(isolationScope);
+    continueCloudflareTrace(context);
 
     return startSpan(
       {
diff --git a/packages/cloudflare/src/instrumentations/worker/instrumentQueue.ts b/packages/cloudflare/src/instrumentations/worker/instrumentQueue.ts
index b12f01474d6a..aea6ebb05d75 100644
--- a/packages/cloudflare/src/instrumentations/worker/instrumentQueue.ts
+++ b/packages/cloudflare/src/instrumentations/worker/instrumentQueue.ts
@@ -10,6 +10,7 @@ import { ensureInstrumented } from '../../instrument';
 import { getFinalOptions } from '../../options';
 import { addCloudResourceContext } from '../../scope-utils';
 import { init } from '../../sdk';
+import { continueCloudflareTrace } from '../../utils/cloudflareTrace';
 import { instrumentContext } from '../../utils/instrumentContext';
 import { setInvocationState } from '../../utils/invocationContext';
 import { instrumentEnv } from './instrumentEnv';
@@ -32,6 +33,7 @@ function wrapQueueHandler(
     isolationScope.setClient(client);
 
     addCloudResourceContext(isolationScope);
+    continueCloudflareTrace(context);
 
     return startSpan(
       {
diff --git a/packages/cloudflare/src/instrumentations/worker/instrumentScheduled.ts b/packages/cloudflare/src/instrumentations/worker/instrumentScheduled.ts
index 8285830b73c1..2cbe32129368 100644
--- a/packages/cloudflare/src/instrumentations/worker/instrumentScheduled.ts
+++ b/packages/cloudflare/src/instrumentations/worker/instrumentScheduled.ts
@@ -21,6 +21,7 @@ import type { CronTriggersIntegration } from '../../integrations/cronTriggers';
 import { getFinalOptions } from '../../options';
 import { addCloudResourceContext } from '../../scope-utils';
 import { init } from '../../sdk';
+import { continueCloudflareTrace } from '../../utils/cloudflareTrace';
 import { instrumentContext } from '../../utils/instrumentContext';
 import { setInvocationState } from '../../utils/invocationContext';
 import { instrumentEnv } from './instrumentEnv';
@@ -40,6 +41,7 @@ function wrapScheduledHandler(
     isolationScope.setClient(client);
 
     addCloudResourceContext(isolationScope);
+    continueCloudflareTrace(context);
 
     const description = `Scheduled Cron ${controller.cron}`;
 
diff --git a/packages/cloudflare/src/utils/cloudflareTrace.ts b/packages/cloudflare/src/utils/cloudflareTrace.ts
new file mode 100644
index 000000000000..7d5bbae1b264
--- /dev/null
+++ b/packages/cloudflare/src/utils/cloudflareTrace.ts
@@ -0,0 +1,50 @@
+import { _INTERNAL_safeMathRandom, getCurrentScope } from '@sentry/core';
+
+interface CloudflareSpanContext {
+  traceId: string;
+  spanId: string;
+}
+
+// The part of `ctx.tracing` the SDK reads. `getActiveSpan` and `Span.spanContext` exist only in
+// newer runtimes, so every member is optional.
+interface CloudflareTracing {
+  getActiveSpan?: () =>
+    | {
+        readonly isTraced?: boolean;
+        spanContext?: () => CloudflareSpanContext;
+      }
+    | undefined;
+}
+
+const TRACE_ID_REGEXP = /^(?!0{32})[0-9a-f]{32}$/;
+const SPAN_ID_REGEXP = /^(?!0{16})[0-9a-f]{16}$/;
+
+/**
+ * Sets the propagation context of the current scope to the Cloudflare trace of the invocation, so
+ * errors, logs and spans get the trace id of the spans that Cloudflare exports.
+ *
+ * Does nothing when Cloudflare does not trace the invocation, or when the runtime does not expose
+ * `Span.spanContext()`. The sampling decision is left to the SDK.
+ */
+export function continueCloudflareTrace(context: unknown): void {
+  let spanContext: CloudflareSpanContext | undefined;
+  try {
+    const span = (context as { tracing?: CloudflareTracing } | undefined)?.tracing?.getActiveSpan?.();
+    spanContext = span?.isTraced ? span.spanContext?.() : undefined;
+  } catch {
+    // Runtime getters on the execution context can throw on foreign or already-torn-down contexts.
+    return;
+  }
+
+  if (!spanContext || !TRACE_ID_REGEXP.test(spanContext.traceId) || !SPAN_ID_REGEXP.test(spanContext.spanId)) {
+    return;
+  }
+
+  // No `dsc` and no `sampled`: the SDK is the head of the Sentry trace, so it samples and builds
+  // the dynamic sampling context itself.
+  getCurrentScope().setPropagationContext({
+    traceId: spanContext.traceId,
+    parentSpanId: spanContext.spanId,
+    sampleRand: _INTERNAL_safeMathRandom(),
+  });
+}
diff --git a/packages/cloudflare/src/wrapRequestHandlerWithInit.ts b/packages/cloudflare/src/wrapRequestHandlerWithInit.ts
index 71444c9a87e3..a2247757ffed 100644
--- a/packages/cloudflare/src/wrapRequestHandlerWithInit.ts
+++ b/packages/cloudflare/src/wrapRequestHandlerWithInit.ts
@@ -27,6 +27,7 @@ import type { CloudflareClient, CloudflareOptions } from './client';
 import type { ExecutionContextCompat } from './executionContext';
 import { flushAndDispose, getOriginalWaitUntil } from './flush';
 import { addCloudResourceContext, addCultureContext, addRequest } from './scope-utils';
+import { continueCloudflareTrace } from './utils/cloudflareTrace';
 import { getInvocationState, getInvocationWaitUntil } from './utils/invocationContext';
 import { withInvocationIsolationScope } from './utils/invocationScope';
 
@@ -158,6 +159,11 @@ export function wrapRequestHandlerWithInit(
     return continueTrace(
       { sentryTrace: request.headers.get('sentry-trace') || '', baggage: request.headers.get('baggage') },
       () => {
+        // An incoming Sentry trace keeps precedence, so traces from instrumented clients stay connected.
+        if (!request.headers.get('sentry-trace')) {
+          continueCloudflareTrace(context);
+        }
+
         // Note: This span will not have a duration unless I/O happens in the handler. This is
         // because of how the cloudflare workers runtime works.
         // See: https://developers.cloudflare.com/workers/runtime-apis/performance/
diff --git a/packages/cloudflare/test/instrumentations/worker/instrumentEmail.test.ts b/packages/cloudflare/test/instrumentations/worker/instrumentEmail.test.ts
index 2c15f5a39966..eda2b0c13af6 100644
--- a/packages/cloudflare/test/instrumentations/worker/instrumentEmail.test.ts
+++ b/packages/cloudflare/test/instrumentations/worker/instrumentEmail.test.ts
@@ -279,6 +279,38 @@ describe('instrumentEmail', () => {
         trace_id: expect.stringMatching(/[a-f0-9]{32}/),
       });
     });
+
+    test('makes the email span a child of the Cloudflare span', async () => {
+      let rootSpan: ReturnType<typeof SentryCore.spanToJSON> | undefined;
+      const handler = {
+        email(_message, _env, _context) {
+          const activeSpan = SentryCore.getActiveSpan();
+          rootSpan = activeSpan ? SentryCore.spanToJSON(SentryCore.getRootSpan(activeSpan)) : undefined;
+        },
+      } satisfies ExportedHandler<typeof MOCK_ENV>;
+
+      const wrappedHandler = withSentry(env => ({ dsn: env.SENTRY_DSN, tracesSampleRate: 1 }), handler);
+      const context = {
+        ...createMockExecutionContext(),
+        tracing: {
+          getActiveSpan: () => ({
+            isTraced: true,
+            spanContext: () => ({
+              traceId: 'a1b2c3d4e5f60718293a4b5c6d7e8f90',
+              spanId: 'b1c2d3e4f5a60718',
+              traceFlags: 1,
+            }),
+          }),
+        },
+      } as unknown as ExecutionContext;
+
+      await wrappedHandler.email?.(createMockEmailMessage(), MOCK_ENV, context);
+
+      expect(rootSpan).toMatchObject({
+        trace_id: 'a1b2c3d4e5f60718293a4b5c6d7e8f90',
+        parent_span_id: 'b1c2d3e4f5a60718',
+      });
+    });
   });
 
   test('flush must be called when all waitUntil are done', async () => {
diff --git a/packages/cloudflare/test/instrumentations/worker/instrumentQueue.test.ts b/packages/cloudflare/test/instrumentations/worker/instrumentQueue.test.ts
index afe51790adfd..1c404289773b 100644
--- a/packages/cloudflare/test/instrumentations/worker/instrumentQueue.test.ts
+++ b/packages/cloudflare/test/instrumentations/worker/instrumentQueue.test.ts
@@ -295,6 +295,38 @@ describe('instrumentQueue', () => {
         trace_id: expect.stringMatching(/[a-f0-9]{32}/),
       });
     });
+
+    test('makes the queue span a child of the Cloudflare span', async () => {
+      let rootSpan: ReturnType<typeof SentryCore.spanToJSON> | undefined;
+      const handler = {
+        queue(_batch, _env, _context) {
+          const activeSpan = SentryCore.getActiveSpan();
+          rootSpan = activeSpan ? SentryCore.spanToJSON(SentryCore.getRootSpan(activeSpan)) : undefined;
+        },
+      } satisfies ExportedHandler<typeof MOCK_ENV>;
+
+      const wrappedHandler = withSentry(env => ({ dsn: env.SENTRY_DSN, tracesSampleRate: 1 }), handler);
+      const context = {
+        ...createMockExecutionContext(),
+        tracing: {
+          getActiveSpan: () => ({
+            isTraced: true,
+            spanContext: () => ({
+              traceId: 'a1b2c3d4e5f60718293a4b5c6d7e8f90',
+              spanId: 'b1c2d3e4f5a60718',
+              traceFlags: 1,
+            }),
+          }),
+        },
+      } as unknown as ExecutionContext;
+
+      await wrappedHandler.queue?.(createMockQueueBatch(), MOCK_ENV, context);
+
+      expect(rootSpan).toMatchObject({
+        trace_id: 'a1b2c3d4e5f60718293a4b5c6d7e8f90',
+        parent_span_id: 'b1c2d3e4f5a60718',
+      });
+    });
   });
 
   test('flush must be called when all waitUntil are done', async () => {
diff --git a/packages/cloudflare/test/instrumentations/worker/instrumentScheduled.test.ts b/packages/cloudflare/test/instrumentations/worker/instrumentScheduled.test.ts
index 843683be8925..dac85e65ea8d 100644
--- a/packages/cloudflare/test/instrumentations/worker/instrumentScheduled.test.ts
+++ b/packages/cloudflare/test/instrumentations/worker/instrumentScheduled.test.ts
@@ -305,6 +305,38 @@ describe('instrumentScheduled', () => {
     test('keeps the descriptive span name when span streaming is disabled', async () => {
       expect(await spanNameFor('static')).toBe('Scheduled Cron 0 0 0 * * *');
     });
+
+    test('makes the scheduled span a child of the Cloudflare span', async () => {
+      let rootSpan: ReturnType<typeof SentryCore.spanToJSON> | undefined;
+      const handler = {
+        scheduled(_controller, _env, _context) {
+          const activeSpan = SentryCore.getActiveSpan();
+          rootSpan = activeSpan ? SentryCore.spanToJSON(SentryCore.getRootSpan(activeSpan)) : undefined;
+        },
+      } satisfies ExportedHandler<typeof MOCK_ENV>;
+
+      const wrappedHandler = withSentry(env => ({ dsn: env.SENTRY_DSN, tracesSampleRate: 1 }), handler);
+      const context = {
+        ...createMockExecutionContext(),
+        tracing: {
+          getActiveSpan: () => ({
+            isTraced: true,
+            spanContext: () => ({
+              traceId: 'a1b2c3d4e5f60718293a4b5c6d7e8f90',
+              spanId: 'b1c2d3e4f5a60718',
+              traceFlags: 1,
+            }),
+          }),
+        },
+      } as unknown as ExecutionContext;
+
+      await wrappedHandler.scheduled?.(createMockScheduledController(), MOCK_ENV, context);
+
+      expect(rootSpan).toMatchObject({
+        trace_id: 'a1b2c3d4e5f60718293a4b5c6d7e8f90',
+        parent_span_id: 'b1c2d3e4f5a60718',
+      });
+    });
   });
 
   describe('cron monitoring', () => {
diff --git a/packages/cloudflare/test/request.test.ts b/packages/cloudflare/test/request.test.ts
index a8c9a3f735f0..d136e68d2ce8 100644
--- a/packages/cloudflare/test/request.test.ts
+++ b/packages/cloudflare/test/request.test.ts
@@ -648,6 +648,87 @@ describe('withSentry', () => {
         links: undefined,
       });
     });
+
+    describe('with a Cloudflare trace', () => {
+      const CLOUDFLARE_TRACE_ID = 'a1b2c3d4e5f60718293a4b5c6d7e8f90';
+      const CLOUDFLARE_SPAN_ID = 'b1c2d3e4f5a60718';
+      const CLOUDFLARE_TRACING = {
+        getActiveSpan: () => ({
+          isTraced: true,
+          spanContext: () => ({ traceId: CLOUDFLARE_TRACE_ID, spanId: CLOUDFLARE_SPAN_ID, traceFlags: 1 }),
+        }),
+      };
+
+      test.each([0, undefined])('attaches errors to the Cloudflare trace with tracesSampleRate %s', async rate => {
+        let sentryEvent: Event = {};
+        await wrapRequestHandler(
+          {
+            options: {
+              dsn: MOCK_OPTIONS.dsn,
+              cacheClient: false,
+              tracesSampleRate: rate,
+              beforeSend(event) {
+                sentryEvent = event;
+                return null;
+              },
+            },
+            request: new Request('https://example.com'),
+            context: { ...createMockExecutionContext(), tracing: CLOUDFLARE_TRACING } as unknown as ExecutionContext,
+          },
+          () => {
+            SentryCore.captureException(new Error('test'));
+            return new Response('test');
+          },
+        );
+
+        expect(sentryEvent.contexts?.trace?.trace_id).toBe(CLOUDFLARE_TRACE_ID);
+      });
+
+      test('makes the request span a child of the Cloudflare span', async () => {
+        let rootSpan: ReturnType<typeof SentryCore.spanToJSON> | undefined;
+        await wrapRequestHandler(
+          {
+            options: { dsn: MOCK_OPTIONS.dsn, cacheClient: false, tracesSampleRate: 1 },
+            request: new Request('https://example.com'),
+            context: { ...createMockExecutionContext(), tracing: CLOUDFLARE_TRACING } as unknown as ExecutionContext,
+          },
+          () => {
+            const activeSpan = SentryCore.getActiveSpan();
+            rootSpan = activeSpan ? SentryCore.spanToJSON(SentryCore.getRootSpan(activeSpan)) : undefined;
+            return new Response('test');
+          },
+        );
+
+        expect(rootSpan).toMatchObject({ trace_id: CLOUDFLARE_TRACE_ID, parent_span_id: CLOUDFLARE_SPAN_ID });
+      });
+
+      test('prefers an incoming sentry-trace header', async () => {
+        const request = new Request('https://example.com');
+        request.headers.set('sentry-trace', '12312012123120121231201212312012-1121201211212012');
+
+        let sentryEvent: Event = {};
+        await wrapRequestHandler(
+          {
+            options: {
+              dsn: MOCK_OPTIONS.dsn,
+              cacheClient: false,
+              beforeSend(event) {
+                sentryEvent = event;
+                return null;
+              },
+            },
+            request,
+            context: { ...createMockExecutionContext(), tracing: CLOUDFLARE_TRACING } as unknown as ExecutionContext,
+          },
+          () => {
+            SentryCore.captureException(new Error('test'));
+            return new Response('test');
+          },
+        );
+
+        expect(sentryEvent.contexts?.trace?.trace_id).toBe('12312012123120121231201212312012');
+      });
+    });
   });
 });
 
diff --git a/packages/cloudflare/test/utils/cloudflareTrace.test.ts b/packages/cloudflare/test/utils/cloudflareTrace.test.ts
new file mode 100644
index 000000000000..39e230d0000b
--- /dev/null
+++ b/packages/cloudflare/test/utils/cloudflareTrace.test.ts
@@ -0,0 +1,93 @@
+import { getCurrentScope, withScope } from '@sentry/core';
+import { describe, expect, it } from 'vitest';
+import { continueCloudflareTrace } from '../../src/utils/cloudflareTrace';
+
+const CLOUDFLARE_TRACE_ID = 'a1b2c3d4e5f60718293a4b5c6d7e8f90';
+const CLOUDFLARE_SPAN_ID = 'b1c2d3e4f5a60718';
+
+describe('continueCloudflareTrace()', () => {
+  it('continues the trace of a traced Cloudflare span', () => {
+    const context = {
+      tracing: {
+        getActiveSpan: () => ({
+          isTraced: true,
+          spanContext: () => ({ traceId: CLOUDFLARE_TRACE_ID, spanId: CLOUDFLARE_SPAN_ID, traceFlags: 1 }),
+        }),
+      },
+    };
+
+    withScope(() => {
+      continueCloudflareTrace(context);
+
+      expect(getCurrentScope().getPropagationContext()).toEqual({
+        traceId: CLOUDFLARE_TRACE_ID,
+        parentSpanId: CLOUDFLARE_SPAN_ID,
+        sampleRand: expect.any(Number),
+      });
+    });
+  });
+
+  it.each([
+    ['there is no execution context', undefined],
+    ['the runtime has no tracing API', {}],
+    ['the runtime has no getActiveSpan', { tracing: {} }],
+    ['there is no active span', { tracing: { getActiveSpan: () => undefined } }],
+    [
+      'the runtime has no spanContext',
+      {
+        tracing: { getActiveSpan: () => ({ isTraced: true }) },
+      },
+    ],
+    [
+      'Cloudflare does not trace the invocation',
+      {
+        tracing: {
+          getActiveSpan: () => ({
+            isTraced: false,
+            spanContext: () => ({ traceId: CLOUDFLARE_TRACE_ID, spanId: CLOUDFLARE_SPAN_ID, traceFlags: 0 }),
+          }),
+        },
+      },
+    ],
+    [
+      'the span context has null ids',
+      {
+        tracing: {
+          getActiveSpan: () => ({
+            isTraced: true,
+            spanContext: () => ({ traceId: '0'.repeat(32), spanId: '0'.repeat(16), traceFlags: 0 }),
+          }),
+        },
+      },
+    ],
+    [
+      'the span context has malformed ids',
+      {
+        tracing: {
+          getActiveSpan: () => ({
+            isTraced: true,
+            spanContext: () => ({ traceId: 'not-a-trace-id', spanId: CLOUDFLARE_SPAN_ID, traceFlags: 1 }),
+          }),
+        },
+      },
+    ],
+    [
+      'reading the active span throws',
+      {
+        tracing: {
+          getActiveSpan: () => {
+            throw new Error('torn down');
+          },
+        },
+      },
+    ],
+  ])('keeps the propagation context when %s', (_, context) => {
+    withScope(scope => {
+      const propagationContext = scope.getPropagationContext();
+
+      continueCloudflareTrace(context);
+
+      expect(scope.getPropagationContext()).toBe(propagationContext);
+    });
+  });
+});