diff --git a/setup/mscs/msc2946/msc2946.go b/setup/mscs/msc2946/msc2946.go
index 03af06669..a125fd78d 100644
--- a/setup/mscs/msc2946/msc2946.go
+++ b/setup/mscs/msc2946/msc2946.go
@@ -70,11 +70,11 @@ func Enable(
 		}
 	})
 
-	base.PublicClientAPIMux.Handle("/unstable/rooms/{roomID}/spaces",
+	base.PublicClientAPIMux.Handle("/unstable/org.matrix.msc2946/rooms/{roomID}/spaces",
 		httputil.MakeAuthAPI("spaces", userAPI, spacesHandler(db, rsAPI, fsAPI, base.Cfg.Global.ServerName)),
 	).Methods(http.MethodPost, http.MethodOptions)
 
-	base.PublicFederationAPIMux.Handle("/unstable/spaces/{roomID}", httputil.MakeExternalAPI(
+	base.PublicFederationAPIMux.Handle("/unstable/org.matrix.msc2946/spaces/{roomID}", httputil.MakeExternalAPI(
 		"msc2946_fed_spaces", func(req *http.Request) util.JSONResponse {
 			fedReq, errResp := gomatrixserverlib.VerifyHTTPRequest(
 				req, time.Now(), base.Cfg.Global.ServerName, keyRing,
diff --git a/setup/mscs/msc2946/msc2946_test.go b/setup/mscs/msc2946/msc2946_test.go
index 4f180a988..99085c0f4 100644
--- a/setup/mscs/msc2946/msc2946_test.go
+++ b/setup/mscs/msc2946/msc2946_test.go
@@ -309,7 +309,7 @@ func postSpaces(t *testing.T, expectCode int, accessToken, roomID string, req *g
 		t.Fatalf("failed to marshal request: %s", err)
 	}
 	httpReq, err := http.NewRequest(
-		"POST", "http://localhost:8010/_matrix/client/unstable/rooms/"+url.PathEscape(roomID)+"/spaces",
+		"POST", "http://localhost:8010/_matrix/client/unstable/org.matrix.msc2946/rooms/"+url.PathEscape(roomID)+"/spaces",
 		bytes.NewBuffer(data),
 	)
 	httpReq.Header.Set("Authorization", "Bearer "+accessToken)