diff --git a/packages/next/src/client/components/parallel-route-default.tsx b/packages/next/src/client/components/parallel-route-default.tsx
index 4c938945f6e55..8ea1065713ea6 100644
--- a/packages/next/src/client/components/parallel-route-default.tsx
+++ b/packages/next/src/client/components/parallel-route-default.tsx
@@ -1,3 +1,5 @@
+import { notFound } from './not-found'
+
 export default function NoopParallelRouteDefault() {
-  return null
+  notFound()
 }
diff --git a/test/e2e/app-dir/parallel-routes-and-interception/app/intercepting-parallel-modal/[username]/@modal/default.js b/test/e2e/app-dir/parallel-routes-and-interception/app/intercepting-parallel-modal/[username]/@modal/default.js
new file mode 100644
index 0000000000000..a6a4d62eae872
--- /dev/null
+++ b/test/e2e/app-dir/parallel-routes-and-interception/app/intercepting-parallel-modal/[username]/@modal/default.js
@@ -0,0 +1,3 @@
+export default function Page({ params }) {
+  return <div>default modal slot</div>
+}
diff --git a/test/e2e/app-dir/parallel-routes-and-interception/parallel-routes-and-interception.test.ts b/test/e2e/app-dir/parallel-routes-and-interception/parallel-routes-and-interception.test.ts
index d0343dd8bffff..fc44c95998d4d 100644
--- a/test/e2e/app-dir/parallel-routes-and-interception/parallel-routes-and-interception.test.ts
+++ b/test/e2e/app-dir/parallel-routes-and-interception/parallel-routes-and-interception.test.ts
@@ -185,6 +185,27 @@ createNextDescribe(
         expect(html).toContain('parallel/(new)/layout')
         expect(html).toContain('parallel/(new)/@baz/nested/page')
       })
+
+      it('should throw a 404 when no matching parallel route is found', async () => {
+        const browser = await next.browser('/parallel-tab-bar')
+        // we make sure the page is available through navigating
+        await check(
+          () => browser.waitForElementByCss('#home').text(),
+          'Tab bar page (@children)'
+        )
+        await browser.elementByCss('#view-duration-link').click()
+        await check(
+          () => browser.waitForElementByCss('#view-duration').text(),
+          'View duration'
+        )
+
+        // fetch /parallel-tab-bar/view-duration
+        const res = await next.fetch(
+          `${next.url}/parallel-tab-bar/view-duration`
+        )
+        const html = await res.text()
+        expect(html).toContain('page could not be found')
+      })
     })
 
     describe('route intercepting', () => {