diff --git a/packages/wallet-webui/src/ui/Shell.tsx b/packages/wallet-webui/src/ui/Shell.tsx
index e13a98baa..51d048224 100644
--- a/packages/wallet-webui/src/ui/Shell.tsx
+++ b/packages/wallet-webui/src/ui/Shell.tsx
@@ -1,4 +1,5 @@
 import type { ComponentChildren } from "preact";
+import { useEffect, useState } from "preact/hooks";
 import { Link, useLocation } from "wouter-preact";
 import { WalletBrand } from "./WalletBrand.js";
 import { WalletIcon, type WalletIconName } from "./WalletIcon.js";
@@ -17,6 +18,7 @@ export function Shell(props: {
   };
 }) {
   const [location] = useLocation();
+  const online = useBrowserOnline();
   const route = location.split("?", 1)[0];
   const selected = (href: string) =>
     href === "/"
@@ -38,6 +40,14 @@ export function Shell(props: {
   const balancesLabel = i18n.str`Balances`;
   return (
     <div class="min-h-screen bg-background pb-24 text-onBackground md:pb-0">
+      {!online && (
+        <p
+          role="status"
+          class="bg-errorContainer px-4 py-2 text-center text-sm font-medium text-onErrorContainer"
+        >{
+          /* Translators: Shown while the browser reports that the device has no network connection. */ i18n.str`No internet connection. The wallet will continue when you are back online.`
+        }</p>
+      )}
       <header
         class={`${props.demo ? "block" : "hidden"} border-b border-outlineVariant bg-surface md:block`}
       >
@@ -211,3 +221,21 @@ function MobileNav(props: {
     </Link>
   );
 }
+
+/** The browser's own idea of network connectivity (navigator.onLine). */
+function useBrowserOnline(): boolean {
+  const [online, setOnline] = useState(
+    typeof navigator === "undefined" ? true : navigator.onLine,
+  );
+  useEffect(() => {
+    const update = () => setOnline(navigator.onLine);
+    window.addEventListener("online", update);
+    window.addEventListener("offline", update);
+    update();
+    return () => {
+      window.removeEventListener("online", update);
+      window.removeEventListener("offline", update);
+    };
+  }, []);
+  return online;
+}