diff --git a/html/webappapis/system-state-and-capabilities/the-navigator-object/navigator_user_agent.https.html b/html/webappapis/system-state-and-capabilities/the-navigator-object/navigator_user_agent.https.html
index 0fb9e372b0dd6f..9409dd08e4d0e7 100644
--- a/html/webappapis/system-state-and-capabilities/the-navigator-object/navigator_user_agent.https.html
+++ b/html/webappapis/system-state-and-capabilities/the-navigator-object/navigator_user_agent.https.html
@@ -1,10 +1,11 @@
 <!DOCTYPE html>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
-<script src="/webrtc/dictionary-helper.js"></script>
 <script>
   test(t => {
     assert_true("userAgentData" in navigator);
+    assert_true("NavigatorUAData" in window);
+    assert_equals(typeof self.NavigatorUAData, "function")
   }, "navigator.userAgentData is exposed.");
 
   promise_test(async t => {
diff --git a/workers/WorkerNavigator_userAgentData.http.html b/workers/WorkerNavigator_userAgentData.http.html
new file mode 100644
index 00000000000000..46c54359dc3941
--- /dev/null
+++ b/workers/WorkerNavigator_userAgentData.http.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<title> WorkerNavigator.userAgentData </title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id=log></div>
+<script>
+
+  promise_test(async () => {
+    const e = await new Promise((resolve, reject) => {
+      const worker = new Worker("./support/WorkerNavigator.js");
+      worker.onmessage = resolve;
+    });
+
+    assert_equals(e.data.uaList, undefined);
+    assert_equals(e.data.mobile, undefined);
+    assert_equals(e.data.getHighEntropyValues, undefined);
+  }, "Test userAgentData in workers");
+</script>
diff --git a/workers/WorkerNavigator_userAgentData.https.html b/workers/WorkerNavigator_userAgentData.https.html
new file mode 100644
index 00000000000000..002c2f09710e33
--- /dev/null
+++ b/workers/WorkerNavigator_userAgentData.https.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<title> WorkerNavigator.userAgentData </title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id=log></div>
+<script>
+
+  promise_test(async () => {
+    const e = await new Promise((resolve, reject) => {
+      const worker = new Worker("./support/WorkerNavigator.js");
+      worker.onmessage = resolve;
+    });
+
+    assert_equals(e.data.uaList.length, navigator.userAgentData.uaList.length);
+    for (let i = 0; i < e.data.uaList.length; ++i) {
+      const workerUA = e.data.uaList[i];
+      const windowUA = navigator.userAgentData.uaList[i];
+      assert_equals(workerUA.brand, windowUA.brand);
+      assert_equals(workerUA.version, windowUA.version);
+    }
+    assert_equals(e.data.mobile, navigator.userAgentData.mobile);
+    const highEntropyValues = await navigator.userAgentData.getHighEntropyValues(["platform", "platformVersion", "architecture", "model", "uaFullVersion"]);
+    assert_equals(e.data.model, highEntropyValues.model);
+    assert_equals(e.data.platform, highEntropyValues.platform);
+    assert_equals(e.data.platformVersion, highEntropyValues.platformVersion);
+    assert_equals(e.data.architecture, highEntropyValues.architecture);
+    assert_equals(e.data.uaFullVersion, highEntropyValues.uaFullVersion);
+    assert_equals(e.data.NavigatorUADataExposed, true);
+  }, "Test userAgentData in workers");
+</script>
diff --git a/workers/support/WorkerNavigator.js b/workers/support/WorkerNavigator.js
index 084e45b24585b9..1daeb2b35d5779 100644
--- a/workers/support/WorkerNavigator.js
+++ b/workers/support/WorkerNavigator.js
@@ -1,8 +1,20 @@
-var obj = new Object();
-obj.appName    = navigator.appName;
-obj.appVersion = navigator.appVersion;
-obj.platform   = navigator.platform;
-obj.userAgent  = navigator.userAgent;
-obj.onLine     = navigator.onLine;
-
-postMessage(obj);
+(async () => {
+  var obj = new Object();
+  obj.appName    = navigator.appName;
+  obj.appVersion = navigator.appVersion;
+  obj.platform   = navigator.platform;
+  obj.userAgent  = navigator.userAgent;
+  obj.onLine     = navigator.onLine;
+  if (navigator.userAgentData) {
+    obj.uaList     = navigator.userAgentData.uaList;
+    obj.mobile     = navigator.userAgentData.mobile;
+    const highEntropyValues = await navigator.userAgentData.getHighEntropyValues(["platform", "platformVersion", "architecture", "model", "uaFullVersion"]);
+    obj.platform = highEntropyValues.platform;
+    obj.platformVersion = highEntropyValues.platformVersion;
+    obj.architecture = highEntropyValues.architecture;
+    obj.model = highEntropyValues.model;
+    obj.uaFullVersion = highEntropyValues.uaFullVersion;
+    obj.NavigatorUADataExposed = (typeof self.NavigatorUAData != "undefined");
+  }
+  postMessage(obj);
+})();
