diff --git a/frontend/controller/service-worker.js b/frontend/controller/service-worker.js
index 574fa4d42..5bdbf302f 100644
--- a/frontend/controller/service-worker.js
+++ b/frontend/controller/service-worker.js
@@ -51,6 +51,34 @@ sbp('sbp/selectors/register', {
       await swRegistration.update()
       setInterval(() => sbp('service-worker/update'), HOURS_MILLIS)
 
+      // Send a 'ready' message to the SW and wait back for a response
+      // This way we ensure that Chelonia has been set up
+      await new Promise((resolve, reject) => {
+        const messageChannel = new MessageChannel()
+        messageChannel.port1.onmessage = (event) => {
+          if (event.data.type === 'ready') {
+            resolve()
+          } else {
+            reject(event.data.error)
+          }
+          messageChannel.port1.close()
+        }
+        messageChannel.port1.onmessageerror = () => {
+          reject(new Error('Message error'))
+          messageChannel.port1.close()
+        }
+
+        navigator.serviceWorker.ready.then(() => {
+          navigator.serviceWorker.controller.postMessage({
+            type: 'ready',
+            port: messageChannel.port2
+          }, [messageChannel.port2])
+        }).catch((e) => {
+          reject(e)
+          messageChannel.port1.close()
+        })
+      })
+
       // Keep the service worker alive while the window is open
       // The default idle timeout on Chrome and Firefox is 30 seconds. We send
       // a ping message every 5 seconds to ensure that the worker remains
diff --git a/frontend/controller/serviceworkers/sw-primary.js b/frontend/controller/serviceworkers/sw-primary.js
index 3c3f9b83d..c4e3e7910 100644
--- a/frontend/controller/serviceworkers/sw-primary.js
+++ b/frontend/controller/serviceworkers/sw-primary.js
@@ -244,6 +244,26 @@ self.addEventListener('message', function (event) {
       case 'event':
         sbp('okTurtles.events/emit', event.data.subtype, ...deserializer(event.data.data))
         break
+      case 'ready': {
+        // The 'ready' message is sent by a client (i.e., a tab or window) to
+        // ensure that Chelonia has been setup
+        const port = event.data.port
+        Promise.race([
+          setupChelonia(),
+          new Promise((resolve, reject) => {
+            setTimeout(() => {
+              reject(new Error('Timed out setting up Chelonia'))
+            }, 30e3)
+          })
+        ]).then(() => {
+          port.postMessage({ type: 'ready' })
+        }, (e) => {
+          port.postMessage({ type: 'error', error: e })
+        }).finally(() => {
+          port.close()
+        })
+        break
+      }
       default:
         console.error('[sw] unknown message type:', event.data)
         break
diff --git a/frontend/setupChelonia.js b/frontend/setupChelonia.js
index 625c3880f..4b3971e6b 100644
--- a/frontend/setupChelonia.js
+++ b/frontend/setupChelonia.js
@@ -310,6 +310,7 @@ export default ((() => {
   return () => {
     if (!promise) {
       promise = setupChelonia().catch((e) => {
+        console.error('[setupChelonia] Error during chelonia setup', e)
         promise = undefined // Reset on error
         throw e // Re-throw the error
       })