diff --git a/components/script/dom/navigator.rs b/components/script/dom/navigator.rs
index ffbf2546a80..ee67359f859 100644
--- a/components/script/dom/navigator.rs
+++ b/components/script/dom/navigator.rs
@@ -222,6 +222,11 @@ impl NavigatorMethods<crate::DomTypeHolder> for Navigator {
         to_frozen_array(&[self.Language()], cx, retval, can_gc)
     }
 
+    /// <https://html.spec.whatwg.org/multipage/#dom-navigator-online>
+    fn OnLine(&self) -> bool {
+        true
+    }
+
     // https://html.spec.whatwg.org/multipage/#dom-navigator-plugins
     fn Plugins(&self) -> DomRoot<PluginArray> {
         self.plugins
diff --git a/components/script/dom/workernavigator.rs b/components/script/dom/workernavigator.rs
index e3a406ed4f8..0b0e90ffd0c 100644
--- a/components/script/dom/workernavigator.rs
+++ b/components/script/dom/workernavigator.rs
@@ -105,6 +105,11 @@ impl WorkerNavigatorMethods<crate::DomTypeHolder> for WorkerNavigator {
         to_frozen_array(&[self.Language()], cx, retval, can_gc)
     }
 
+    /// <https://html.spec.whatwg.org/multipage/#dom-navigator-online>
+    fn OnLine(&self) -> bool {
+        true
+    }
+
     // https://w3c.github.io/permissions/#navigator-and-workernavigator-extension
     fn Permissions(&self) -> DomRoot<Permissions> {
         self.permissions
diff --git a/components/script_bindings/webidls/Navigator.webidl b/components/script_bindings/webidls/Navigator.webidl
index 92f37baa95b..6ac6175f3ca 100644
--- a/components/script_bindings/webidls/Navigator.webidl
+++ b/components/script_bindings/webidls/Navigator.webidl
@@ -9,7 +9,7 @@ interface Navigator {
 };
 Navigator includes NavigatorID;
 Navigator includes NavigatorLanguage;
-//Navigator includes NavigatorOnLine;
+Navigator includes NavigatorOnLine;
 //Navigator includes NavigatorContentUtils;
 //Navigator includes NavigatorStorageUtils;
 Navigator includes NavigatorPlugins;
@@ -43,6 +43,12 @@ interface mixin NavigatorLanguage {
   readonly attribute any languages;
 };
 
+// https://html.spec.whatwg.org/multipage/#dom-navigator-online
+[Exposed=(Window,Worker)]
+interface mixin NavigatorOnLine {
+  readonly attribute boolean onLine;
+};
+
 // https://html.spec.whatwg.org/multipage/#navigatorplugins
 interface mixin NavigatorPlugins {
   [SameObject] readonly attribute PluginArray plugins;
diff --git a/components/script_bindings/webidls/WorkerNavigator.webidl b/components/script_bindings/webidls/WorkerNavigator.webidl
index 33ddfade93d..7e80fe9a009 100644
--- a/components/script_bindings/webidls/WorkerNavigator.webidl
+++ b/components/script_bindings/webidls/WorkerNavigator.webidl
@@ -7,7 +7,7 @@
 interface WorkerNavigator {};
 WorkerNavigator includes NavigatorID;
 WorkerNavigator includes NavigatorLanguage;
-//WorkerNavigator includes NavigatorOnLine;
+WorkerNavigator includes NavigatorOnLine;
 WorkerNavigator includes NavigatorConcurrentHardware;
 
 // https://w3c.github.io/permissions/#navigator-and-workernavigator-extension
diff --git a/tests/wpt/meta/html/browsers/offline/browser-state/navigator_online_online.https.html.ini b/tests/wpt/meta/html/browsers/offline/browser-state/navigator_online_online.https.html.ini
deleted file mode 100644
index 19f382bec2f..00000000000
--- a/tests/wpt/meta/html/browsers/offline/browser-state/navigator_online_online.https.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[navigator_online_online.https.html]
-  [Offline Application Cache - navigator_online_online]
-    expected: FAIL
diff --git a/tests/wpt/meta/html/dom/idlharness.any.js.ini b/tests/wpt/meta/html/dom/idlharness.any.js.ini
index 7d0eb9856b2..f17466adc7f 100644
--- a/tests/wpt/meta/html/dom/idlharness.any.js.ini
+++ b/tests/wpt/meta/html/dom/idlharness.any.js.ini
@@ -185,15 +185,9 @@
   [WorkerNavigator interface: member taintEnabled]
     expected: FAIL
 
-  [WorkerNavigator interface: attribute onLine]
-    expected: FAIL
-
   [WorkerNavigator interface: self.navigator must not have property "taintEnabled"]
     expected: FAIL
 
-  [WorkerNavigator interface: self.navigator must inherit property "onLine" with the proper type]
-    expected: FAIL
-
   [OffscreenCanvasRenderingContext2D interface: operation getContextAttributes()]
     expected: FAIL
 
diff --git a/tests/wpt/meta/html/dom/idlharness.https.html.ini b/tests/wpt/meta/html/dom/idlharness.https.html.ini
index a60e9fcd4af..29cbc17c7e3 100644
--- a/tests/wpt/meta/html/dom/idlharness.https.html.ini
+++ b/tests/wpt/meta/html/dom/idlharness.https.html.ini
@@ -695,9 +695,6 @@
   [CanvasRenderingContext2D interface: document.createElement("canvas").getContext("2d") must inherit property "imageSmoothingQuality" with the proper type]
     expected: FAIL
 
-  [Navigator interface: attribute onLine]
-    expected: FAIL
-
   [OffscreenCanvasRenderingContext2D interface: operation getLineDash()]
     expected: FAIL
 
@@ -5348,9 +5345,6 @@
   [Navigator interface: attribute oscpu]
     expected: FAIL
 
-  [Navigator interface: attribute onLine]
-    expected: FAIL
-
   [Navigator interface: operation registerProtocolHandler(DOMString, USVString)]
     expected: FAIL
 
@@ -5366,9 +5360,6 @@
   [Navigator interface: window.navigator must inherit property "oscpu" with the proper type]
     expected: FAIL
 
-  [Navigator interface: window.navigator must inherit property "onLine" with the proper type]
-    expected: FAIL
-
   [Navigator interface: window.navigator must inherit property "registerProtocolHandler(DOMString, USVString)" with the proper type]
     expected: FAIL
 
diff --git a/tests/wpt/meta/workers/WorkerNavigator.any.js.ini b/tests/wpt/meta/workers/WorkerNavigator.any.js.ini
index 9f6e56150ef..02500985497 100644
--- a/tests/wpt/meta/workers/WorkerNavigator.any.js.ini
+++ b/tests/wpt/meta/workers/WorkerNavigator.any.js.ini
@@ -3,7 +3,3 @@
 
 [WorkerNavigator.any.serviceworker.html]
   expected: ERROR
-
-[WorkerNavigator.any.worker.html]
-  [Testing Navigator properties on workers.]
-    expected: FAIL