diff --git a/public/sw.js b/public/sw.js
index 95121e3c..1f63d459 100644
--- a/public/sw.js
+++ b/public/sw.js
@@ -59,8 +59,9 @@ registerRoute(iconsRoute);
 // - /api/v1/custom_emojis
 // - /api/v1/preferences
 // - /api/v1/lists/:id
+// - /api/v1/announcements
 const apiExtendedRoute = new RegExpRoute(
-  /^https?:\/\/[^\/]+\/api\/v\d+\/(instance|custom_emojis|preferences|lists\/\d+)$/,
+  /^https?:\/\/[^\/]+\/api\/v\d+\/(instance|custom_emojis|preferences|lists\/\d+|announcements)$/,
   new StaleWhileRevalidate({
     cacheName: 'api-extended',
     plugins: [