diff --git a/addons/bus/static/src/services/bus_service.js b/addons/bus/static/src/services/bus_service.js
index 71640baa450..22d6555dd94 100644
--- a/addons/bus/static/src/services/bus_service.js
+++ b/addons/bus/static/src/services/bus_service.js
@@ -25,25 +25,11 @@ export const busService = {
 
     async start(env, { multi_tab: multiTab, "bus.parameters": params }) {
         const bus = new EventBus();
+        let worker;
         let isActive = false;
-        let workerURL = `${params.serverURL}/bus/websocket_worker_bundle?v=${WORKER_VERSION}`;
-        if (params.serverURL !== window.origin) {
-            // Bus service is loaded from a different origin than the bundle
-            // URL. The Worker expects an URL from this origin, give it a base64
-            // URL that will then load the bundle via "importScripts" which
-            // allows cross origin.
-            const source = `importScripts("${workerURL}");`;
-            workerURL = 'data:application/javascript;base64,' + window.btoa(source);
-        }
-        const workerClass = 'SharedWorker' in window && !isIosApp() ? browser.SharedWorker : browser.Worker;
-        const worker = new workerClass(workerURL, {
-            name: 'SharedWorker' in window && !isIosApp() ? 'odoo:websocket_shared_worker' : 'odoo:websocket_worker',
-        });
+        let isInitialized = false;
+        let isUsingSharedWorker = 'SharedWorker' in browser && !isIosApp();
         const connectionInitializedDeferred = new Deferred();
-        worker.addEventListener("error", (e) => {
-            connectionInitializedDeferred.resolve();
-            console.warn("Error while loading 'bus_service' SharedWorker");
-        });
 
         /**
         * Send a message to the worker.
@@ -55,7 +41,7 @@ export const busService = {
         */
         function send(action, data) {
             const message = { action, data };
-            if ('SharedWorker' in window && !isIosApp()) {
+            if (isUsingSharedWorker) {
                 worker.port.postMessage(message);
             } else {
                 worker.postMessage(message);
@@ -76,6 +62,7 @@ export const busService = {
                 multiTab.setSharedValue('last_notification_id', data[data.length - 1].id);
                 data = data.map(notification => notification.message);
             } else if (type === 'initialized') {
+                isInitialized = true;
                 connectionInitializedDeferred.resolve();
                 return;
             }
@@ -108,13 +95,46 @@ export const busService = {
             });
         }
 
-        if ('SharedWorker' in window && !isIosApp()) {
-            worker.port.start();
-            worker.port.addEventListener('message', handleMessage);
-        } else {
-            worker.addEventListener('message', handleMessage);
+        /**
+         * Start the "bus_service" worker.
+         */
+        function startWorker() {
+            let workerURL = `${params.serverURL}/bus/websocket_worker_bundle?v=${WORKER_VERSION}`;
+            if (params.serverURL !== window.origin) {
+                // Bus service is loaded from a different origin than the bundle
+                // URL. The Worker expects an URL from this origin, give it a base64
+                // URL that will then load the bundle via "importScripts" which
+                // allows cross origin.
+                const source = `importScripts("${workerURL}");`;
+                workerURL = 'data:application/javascript;base64,' + window.btoa(source);
+            }
+            const workerClass = isUsingSharedWorker ? browser.SharedWorker : browser.Worker;
+            worker = new workerClass(workerURL, {
+                name: isUsingSharedWorker
+                    ? 'odoo:websocket_shared_worker'
+                    : 'odoo:websocket_worker',
+            });
+            worker.addEventListener("error", (e) => {
+                if (!isInitialized && workerClass === browser.SharedWorker) {
+                    console.warn(
+                        'Error while loading "bus_service" SharedWorker, fallback on Worker.'
+                    );
+                    isUsingSharedWorker = false;
+                    startWorker();
+                } else if (!isInitialized) {
+                    isInitialized = true;
+                    connectionInitializedDeferred.resolve();
+                    console.warn('Bus service failed to initialized.');
+                }
+            });
+            if (isUsingSharedWorker) {
+                worker.port.start();
+                worker.port.addEventListener('message', handleMessage);
+            } else {
+                worker.addEventListener('message', handleMessage);
+            }
+            initializeWorkerConnection();
         }
-        initializeWorkerConnection();
         browser.addEventListener('pagehide', ({ persisted }) => {
             if (!persisted) {
                 // Page is gonna be unloaded, disconnect this client
@@ -128,6 +148,7 @@ export const busService = {
             }
         });
         browser.addEventListener('offline', () => send('stop'));
+        startWorker();
         await connectionInitializedDeferred;
 
         return {
diff --git a/addons/bus/static/tests/bus_tests.js b/addons/bus/static/tests/bus_tests.js
index 4d162754028..e16ffa2c125 100644
--- a/addons/bus/static/tests/bus_tests.js
+++ b/addons/bus/static/tests/bus_tests.js
@@ -547,6 +547,38 @@ QUnit.module('Bus', {
             "reconnect",
         ]);
     });
+
+    QUnit.test(
+        "Fallback on simple worker when shared worker failed to initialize",
+        async function (assert) {
+            const originalSharedWorker = browser.SharedWorker;
+            const originalWorker = browser.Worker;
+            patchWithCleanup(browser, {
+                SharedWorker: function (url, options) {
+                    assert.step("shared-worker creation");
+                    const sw = new originalSharedWorker(url, options);
+                    // Simulate error during shared worker creation.
+                    setTimeout(() => sw.dispatchEvent(new Event("error")));
+                    return sw;
+                },
+                Worker: function (url, options) {
+                    assert.step("worker creation");
+                    return new originalWorker(url, options);
+                },
+            }, { pure: true });
+            patchWithCleanup(window.console, {
+                warn(message) {
+                    assert.step(message);
+                },
+            })
+            await makeTestEnv();
+            assert.verifySteps([
+                "shared-worker creation",
+                "Error while loading \"bus_service\" SharedWorker, fallback on Worker.",
+                "worker creation",
+            ]);
+        }
+    );
 });
 });