diff --git a/portals/portal-activate-data.html b/portals/portal-activate-data.html
new file mode 100644
index 00000000000000..e2417cb7332010
--- /dev/null
+++ b/portals/portal-activate-data.html
@@ -0,0 +1,65 @@
+<!DOCTYPE html>
+<title>Tests passing of data along with portal activation</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+function nextMessage(target) {
+  return new Promise((resolve, reject) => {
+    target.addEventListener('message', e => resolve(e), {once: true});
+  });
+}
+
+async function openPortalAndActivate(logic, activateOptions) {
+  const bc = new BroadcastChannel('portal-activate-data');
+  const w = window.open();
+  try {
+    const portal = w.document.createElement('portal');
+    portal.src = new URL('resources/portal-activate-data-portal.html?logic=' + encodeURIComponent(logic), location.href);
+    w.document.body.appendChild(portal);
+    assert_equals((await nextMessage(bc)).data, 'ready');
+    await portal.activate(activateOptions);
+    return (await nextMessage(bc)).data;
+  } finally {
+    w.close();
+    bc.close();
+  }
+}
+
+promise_test(async () => {
+  const {echo} = await openPortalAndActivate(
+      'return {echo: event.data}',
+      {data: 'banana'});
+  assert_equals(echo, 'banana');
+}, "A string can be passed through activate data.");
+
+promise_test(async () => {
+  let {port1, port2} = new MessageChannel();
+  let replyViaPort = nextMessage(port1);
+  port1.start();
+  let ok = await openPortalAndActivate(
+      'let port2 = event.data; port2.postMessage(42); return true;',
+      {data: port2, transfer: [port2]});
+  assert_true(ok);
+  assert_equals((await replyViaPort).data, 42);
+}, "A message port can be passed through activate data.");
+
+if (window.SharedArrayBuffer) {
+  promise_test(async t => {
+  await promise_rejects(
+      t, 'DataCloneError',
+      openPortalAndActivate('', {data: new SharedArrayBuffer}));
+  }, "A SharedArrayBuffer cannot be passed through activate data.");
+}
+
+promise_test(async t => {
+  await promise_rejects(
+      t, new Error,
+      openPortalAndActivate('', {data: {get a() { throw new Error; }}}));
+}, "Uncloneable data has its exception propagated.");
+
+promise_test(async t => {
+  await promise_rejects(
+      t, new TypeError,
+      openPortalAndActivate('', {data: null, transfer: [null]}));
+}, "Errors during transfer list processing are propagated.");
+</script>
diff --git a/portals/resources/portal-activate-data-portal.html b/portals/resources/portal-activate-data-portal.html
new file mode 100644
index 00000000000000..cba38a005f57a5
--- /dev/null
+++ b/portals/resources/portal-activate-data-portal.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<script>
+const bc = new BroadcastChannel('portal-activate-data');
+let logic = new Function('event', (new URL(location)).searchParams.get('logic'));
+onload = () => bc.postMessage('ready');
+onportalactivate = event => {
+  try {
+    bc.postMessage(logic(event));
+  } finally {
+    bc.close();
+  }
+};
+</script>
