diff --git a/packages/cloudflare/test/integrations/fetch.test.ts b/packages/cloudflare/test/integrations/fetch.test.ts
index 724ff39c7dde..2a8f9cf6e718 100644
--- a/packages/cloudflare/test/integrations/fetch.test.ts
+++ b/packages/cloudflare/test/integrations/fetch.test.ts
@@ -101,8 +101,8 @@ describe('WinterCGFetch instrumentation', () => {
     expect(fetchInstrumentationHandlerCallback).toBeDefined();
 
     const startHandlerData: HandlerDataFetch = {
-      fetchData: { url: 'https://dsn.ingest.sentry.io/1337', method: 'POST' },
-      args: ['https://dsn.ingest.sentry.io/1337'],
+      fetchData: { url: 'https://dsn.ingest.sentry.io/1337?sentry_key=123', method: 'POST' },
+      args: ['https://dsn.ingest.sentry.io/1337?sentry_key=123'],
       startTimestamp: Date.now(),
     };
     fetchInstrumentationHandlerCallback(startHandlerData);
diff --git a/packages/core/src/utils/isSentryRequestUrl.ts b/packages/core/src/utils/isSentryRequestUrl.ts
index e93f61a5919a..c2127cdfeb38 100644
--- a/packages/core/src/utils/isSentryRequestUrl.ts
+++ b/packages/core/src/utils/isSentryRequestUrl.ts
@@ -21,7 +21,12 @@ function checkTunnel(url: string, tunnel: string | undefined): boolean {
 }
 
 function checkDsn(url: string, dsn: DsnComponents | undefined): boolean {
-  return dsn ? url.includes(dsn.host) : false;
+  // Requests to Sentry's ingest endpoint must have a `sentry_key` in the query string
+  // This is equivalent to the public_key which is required in the DSN
+  // see https://develop.sentry.dev/sdk/overview/#parsing-the-dsn
+  // Therefore a request to the same host and with a `sentry_key` in the query string
+  // can be considered a request to the ingest endpoint
+  return dsn ? url.includes(dsn.host) && !!url.match(/sentry_key/) : false;
 }
 
 function removeTrailingSlash(str: string): string {
diff --git a/packages/core/test/lib/utils/isSentryRequestUrl.test.ts b/packages/core/test/lib/utils/isSentryRequestUrl.test.ts
index 195e93493e98..75e8826b2470 100644
--- a/packages/core/test/lib/utils/isSentryRequestUrl.test.ts
+++ b/packages/core/test/lib/utils/isSentryRequestUrl.test.ts
@@ -4,12 +4,17 @@ import type { Client } from '../../../src/client';
 
 describe('isSentryRequestUrl', () => {
   it.each([
-    ['', 'sentry-dsn.com', '', false],
-    ['http://sentry-dsn.com/my-url', 'sentry-dsn.com', '', true],
-    ['http://sentry-dsn.com', 'sentry-dsn.com', '', true],
+    ['http://sentry-dsn.com/my-url?sentry_key=123', 'sentry-dsn.com', '', true],
     ['http://tunnel:4200', 'sentry-dsn.com', 'http://tunnel:4200', true],
     ['http://tunnel:4200', 'sentry-dsn.com', 'http://tunnel:4200/', true],
     ['http://tunnel:4200/', 'sentry-dsn.com', 'http://tunnel:4200', true],
+    ['http://tunnel:4200/', 'another-dsn.com', 'http://tunnel:4200', true],
+
+    ['http://tunnel:4200/?sentry_key=123', 'another-dsn.com', '', false],
+    ['http://sentry-dsn.com/my-url', 'sentry-dsn.com', '', false],
+    ['http://sentry-dsn.com', 'sentry-dsn.com', '', false],
+    ['http://tunnel:4200/', 'another-dsn.com', 'http://tunnel:4200/sentry-tunnel', false],
+    ['', 'sentry-dsn.com', '', false],
     ['http://tunnel:4200/a', 'sentry-dsn.com', 'http://tunnel:4200', false],
   ])('works with url=%s, dsn=%s, tunnel=%s', (url: string, dsn: string, tunnel: string, expected: boolean) => {
     const client = {