diff --git a/e2e/tests/ui/pages/not-found/not-found.spec.ts b/e2e/tests/ui/pages/not-found/not-found.spec.ts
new file mode 100644
index 000000000..44f99e10f
--- /dev/null
+++ b/e2e/tests/ui/pages/not-found/not-found.spec.ts
@@ -0,0 +1,49 @@
+// @ts-check
+
+import { expect } from "@playwright/test";
+
+import { test } from "../../fixtures";
+import { login } from "../../helpers/Auth";
+
+const NON_EXISTENT_UUID = "urn:uuid:00000000-0000-0000-0000-000000000000";
+
+const expectNotFound = async (page: import("@playwright/test").Page) => {
+  await expect(
+    page.getByRole("heading", { name: "404: That page does not exist" }),
+  ).toBeVisible();
+  await expect(
+    page.getByText("Another page might have the information you need."),
+  ).toBeVisible();
+};
+
+test.describe("Not Found page", { tag: "@tier1" }, () => {
+  test.beforeEach(async ({ page }) => {
+    await login(page);
+  });
+
+  test("Shows 404 page for undefined route", async ({ page }) => {
+    await page.goto("/this-page-does-not-exist");
+    await expectNotFound(page);
+  });
+
+  test("Shows 404 page for non-existent advisory", async ({ page }) => {
+    await page.goto(`/advisories/${NON_EXISTENT_UUID}`);
+    await expectNotFound(page);
+  });
+
+  test("Shows 404 page for non-existent SBOM", async ({ page }) => {
+    await page.goto(`/sboms/${NON_EXISTENT_UUID}`);
+    await expectNotFound(page);
+  });
+
+  test("Shows 404 page for non-existent vulnerability", async ({ page }) => {
+    await page.goto("/vulnerabilities/CVE-0000-00000");
+    await expectNotFound(page);
+  });
+
+  // Enable this test when https://issues.redhat.com/browse/TC-3626 is fixed
+  test.skip("Shows 404 page for non-existent package", async ({ page }) => {
+    await page.goto(`/packages/${NON_EXISTENT_UUID}`);
+    await expectNotFound(page);
+  });
+});