diff --git a/keyserver/src/responders/thread-responders.js b/keyserver/src/responders/thread-responders.js
--- a/keyserver/src/responders/thread-responders.js
+++ b/keyserver/src/responders/thread-responders.js
@@ -179,6 +179,7 @@
     threadID: tID,
     calendarQuery: t.maybe(entryQueryInputValidator),
     inviteLinkSecret: t.maybe(t.String),
+    autoJoin: t.maybe(t.Boolean),
   });
 
 async function threadJoinResponder(
diff --git a/keyserver/src/updaters/thread-updaters.js b/keyserver/src/updaters/thread-updaters.js
--- a/keyserver/src/updaters/thread-updaters.js
+++ b/keyserver/src/updaters/thread-updaters.js
@@ -827,7 +827,7 @@
     fetchViewerIsMember(viewer, request.threadID),
     permissionCheck,
   ]);
-  if (!hasPermission) {
+  if (!hasPermission && !request.autoJoin) {
     throw new ServerError('invalid_parameters');
   }
 
@@ -855,7 +855,11 @@
     }
   }
 
-  const changeset = await changeRole(request.threadID, [viewer.userID], null);
+  const changeset = await changeRole(request.threadID, [viewer.userID], null, {
+    ...(request.autoJoin && {
+      defaultSubscription: { home: false, pushNotifs: false },
+    }),
+  });
 
   const membershipResult = await commitMembershipChangeset(viewer, changeset, {
     calendarQuery,
diff --git a/lib/types/thread-types.js b/lib/types/thread-types.js
--- a/lib/types/thread-types.js
+++ b/lib/types/thread-types.js
@@ -302,11 +302,13 @@
   +threadID: string,
   +calendarQuery?: ?CalendarQuery,
   +inviteLinkSecret?: string,
+  +autoJoin?: boolean,
 };
 export type ClientThreadJoinRequest = {
   +threadID: string,
   +calendarQuery: CalendarQuery,
   +inviteLinkSecret?: string,
+  +autoJoin?: boolean,
 };
 export type ThreadJoinResult = {
   +updatesResult: {
diff --git a/native/components/auto-join-community-handler.react.js b/native/components/auto-join-community-handler.react.js
--- a/native/components/auto-join-community-handler.react.js
+++ b/native/components/auto-join-community-handler.react.js
@@ -66,6 +66,7 @@
             { type: 'threads', threadIDs: [communityID] },
           ],
         },
+        autoJoin: true,
       });
     },
     [calendarQuery, joinThread],