diff --git a/dev-packages/browser-integration-tests/suites/profiling/manualMode/test.ts b/dev-packages/browser-integration-tests/suites/profiling/manualMode/test.ts
index 2e4358563aa2..176caad92af6 100644
--- a/dev-packages/browser-integration-tests/suites/profiling/manualMode/test.ts
+++ b/dev-packages/browser-integration-tests/suites/profiling/manualMode/test.ts
@@ -48,7 +48,7 @@ sentryTest('sends profile_chunk envelopes in manual mode', async ({ page, getLoc
   const envelopeItemHeader = profileChunkEnvelopeItem[0];
   const envelopeItemPayload1 = profileChunkEnvelopeItem[1];
 
-  expect(envelopeItemHeader).toHaveProperty('type', 'profile_chunk');
+  expect(envelopeItemHeader).toEqual({ type: 'profile_chunk', platform: 'javascript' });
   expect(envelopeItemPayload1.profile).toBeDefined();
 
   const profilerId1 = envelopeItemPayload1.profiler_id;
@@ -71,7 +71,7 @@ sentryTest('sends profile_chunk envelopes in manual mode', async ({ page, getLoc
   const envelopeItemHeader2 = profileChunkEnvelopeItem2[0];
   const envelopeItemPayload2 = profileChunkEnvelopeItem2[1];
 
-  expect(envelopeItemHeader2).toHaveProperty('type', 'profile_chunk');
+  expect(envelopeItemHeader2).toEqual({ type: 'profile_chunk', platform: 'javascript' });
   expect(envelopeItemPayload2.profile).toBeDefined();
 
   expect(envelopeItemPayload2.profiler_id).toBe(profilerId1); // same profiler id for the whole session
diff --git a/dev-packages/browser-integration-tests/suites/profiling/traceLifecycleMode_multiple-chunks/test.ts b/dev-packages/browser-integration-tests/suites/profiling/traceLifecycleMode_multiple-chunks/test.ts
index 5afc23a3a75f..a16a054da45a 100644
--- a/dev-packages/browser-integration-tests/suites/profiling/traceLifecycleMode_multiple-chunks/test.ts
+++ b/dev-packages/browser-integration-tests/suites/profiling/traceLifecycleMode_multiple-chunks/test.ts
@@ -51,7 +51,7 @@ sentryTest(
     const envelopeItemHeader = profileChunkEnvelopeItem[0];
     const envelopeItemPayload1 = profileChunkEnvelopeItem[1];
 
-    expect(envelopeItemHeader).toHaveProperty('type', 'profile_chunk');
+    expect(envelopeItemHeader).toEqual({ type: 'profile_chunk', platform: 'javascript' });
     expect(envelopeItemPayload1.profile).toBeDefined();
 
     validateProfilePayloadMetadata(envelopeItemPayload1);
@@ -77,7 +77,7 @@ sentryTest(
     const envelopeItemHeader2 = profileChunkEnvelopeItem2[0];
     const envelopeItemPayload2 = profileChunkEnvelopeItem2[1];
 
-    expect(envelopeItemHeader2).toHaveProperty('type', 'profile_chunk');
+    expect(envelopeItemHeader2).toEqual({ type: 'profile_chunk', platform: 'javascript' });
     expect(envelopeItemPayload2.profile).toBeDefined();
 
     validateProfilePayloadMetadata(envelopeItemPayload2);
diff --git a/dev-packages/browser-integration-tests/suites/profiling/traceLifecycleMode_overlapping-spans/test.ts b/dev-packages/browser-integration-tests/suites/profiling/traceLifecycleMode_overlapping-spans/test.ts
index fa66a225b49b..487cd05f1dbd 100644
--- a/dev-packages/browser-integration-tests/suites/profiling/traceLifecycleMode_overlapping-spans/test.ts
+++ b/dev-packages/browser-integration-tests/suites/profiling/traceLifecycleMode_overlapping-spans/test.ts
@@ -52,7 +52,7 @@ sentryTest(
     const envelopeItemHeader = profileChunkEnvelopeItem[0];
     const envelopeItemPayload = profileChunkEnvelopeItem[1];
 
-    expect(envelopeItemHeader).toHaveProperty('type', 'profile_chunk');
+    expect(envelopeItemHeader).toEqual({ type: 'profile_chunk', platform: 'javascript' });
     expect(envelopeItemPayload.profile).toBeDefined();
 
     validateProfilePayloadMetadata(envelopeItemPayload);
diff --git a/packages/browser/src/profiling/UIProfiler.ts b/packages/browser/src/profiling/UIProfiler.ts
index 89edb4899a6a..932b442a4b6e 100644
--- a/packages/browser/src/profiling/UIProfiler.ts
+++ b/packages/browser/src/profiling/UIProfiler.ts
@@ -401,7 +401,7 @@ export class UIProfiler implements ContinuousProfiler<Client> {
         ...(sdkInfo && { sdk: sdkInfo }),
         ...(!!tunnel && dsn && { dsn: dsnToString(dsn) }),
       },
-      [[{ type: 'profile_chunk' }, chunk]],
+      [[{ type: 'profile_chunk', platform: 'javascript' }, chunk]],
     );
 
     client.sendEnvelope(envelope).then(null, reason => {
diff --git a/packages/browser/test/profiling/UIProfiler.test.ts b/packages/browser/test/profiling/UIProfiler.test.ts
index 7fd583f513d8..b64ee35fc50e 100644
--- a/packages/browser/test/profiling/UIProfiler.test.ts
+++ b/packages/browser/test/profiling/UIProfiler.test.ts
@@ -106,6 +106,7 @@ describe('Browser Profiling v2 trace lifecycle', () => {
       const transactionEnvelopeHeader = send.mock.calls?.[0]?.[0]?.[1]?.[0]?.[0];
       const profileChunkEnvelopeHeader = send.mock.calls?.[1]?.[0]?.[1]?.[0]?.[0];
       expect(profileChunkEnvelopeHeader?.type).toBe('profile_chunk');
+      expect(profileChunkEnvelopeHeader?.platform).toBe('javascript');
       expect(transactionEnvelopeHeader?.type).toBe('transaction');
     });
 
@@ -207,6 +208,7 @@ describe('Browser Profiling v2 trace lifecycle', () => {
       expect(mockConstructor.mock.calls.length).toBe(2);
       const firstChunkHeader = send.mock.calls?.[0]?.[0]?.[1]?.[0]?.[0];
       expect(firstChunkHeader?.type).toBe('profile_chunk');
+      expect(firstChunkHeader?.platform).toBe('javascript');
 
       // Second chunk after another 60s
       vi.advanceTimersByTime(60_000);
@@ -679,6 +681,7 @@ describe('Browser Profiling v2 manual lifecycle', () => {
     expect(send).toHaveBeenCalledTimes(1);
     const envelopeHeader = send.mock.calls?.[0]?.[0]?.[1]?.[0]?.[0];
     expect(envelopeHeader?.type).toBe('profile_chunk');
+    expect(envelopeHeader?.platform).toBe('javascript');
   });
 
   it('calling start and stop while profile session is running prints warnings', async () => {