diff --git a/CHANGELOG.md b/CHANGELOG.md
index acb90c0b..4ebe8666 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,8 @@
 > [!CAUTION]
 > **This is a prerelease intended for test and experimental purposes only!**
 
+- Fixed realtime 403 API error on resubscribe ([#5674](https://github.com/pocketbase/pocketbase/issues/5674)).
+
 - Fixed the auto OAuth2 avatar mapped field assignment when the OAuth2 provider doesn't return an avatar URL ([#5673](https://github.com/pocketbase/pocketbase/pull/5673)).
   _In case the avatar retrieval fails and the mapped record field "Required" option is not set, the error is silenced and only logged with WARN level._
 
diff --git a/apis/realtime.go b/apis/realtime.go
index 9262ba6b..dab452ff 100644
--- a/apis/realtime.go
+++ b/apis/realtime.go
@@ -185,10 +185,9 @@ func realtimeSetSubscriptions(e *core.RequestEvent) error {
 		return e.NotFoundError("Missing or invalid client id.", err)
 	}
 
-	// check if the previous request was authorized
-	oldAuthId := extractAuthIdFromGetter(client)
-	newAuthId := extractAuthIdFromGetter(e)
-	if oldAuthId != "" && oldAuthId != newAuthId {
+	// for now allow only guest->auth upgrades and any other auth change is forbidden
+	clientAuth, _ := client.Get(RealtimeClientAuthKey).(*core.Record)
+	if clientAuth != nil && !isSameAuth(clientAuth, e.Auth) {
 		return e.ForbiddenError("The current and the previous request authorization don't match.", nil)
 	}
 
@@ -535,8 +534,8 @@ func realtimeBroadcastRecord(app core.App, action string, record *core.Record, d
 							// ignore the auth record email visibility checks
 							// for auth owner, superuser or manager
 							if collection.IsAuth() {
-								authId := extractAuthIdFromGetter(client)
-								if authId == cleanRecord.Id ||
+								clientAuth, _ := client.Get(RealtimeClientAuthKey).(*core.Record)
+								if isSameAuth(clientAuth, cleanRecord) ||
 									realtimeCanAccessRecord(app, cleanRecord, requestInfo, collection.ManageRule) {
 									cleanRecord.IgnoreEmailVisibility(true)
 								}
@@ -681,17 +680,16 @@ func realtimeUnsetDryCachedRecord(app core.App, action string, record *core.Reco
 	return group.Wait()
 }
 
-type getter interface {
-	Get(string) any
-}
-
-func extractAuthIdFromGetter(val getter) string {
-	record, _ := val.Get(RealtimeClientAuthKey).(*core.Record)
-	if record != nil {
-		return record.Id
+func isSameAuth(authA, authB *core.Record) bool {
+	if authA == nil {
+		return authB == nil
 	}
 
-	return ""
+	if authB == nil {
+		return false
+	}
+
+	return authA.Id == authB.Id && authA.Collection().Id == authB.Collection().Id
 }
 
 // realtimeCanAccessRecord checks if the subscription client has access to the specified record model.
diff --git a/apis/realtime_test.go b/apis/realtime_test.go
index 414e1579..f7c920f8 100644
--- a/apis/realtime_test.go
+++ b/apis/realtime_test.go
@@ -233,7 +233,7 @@ func TestRealtimeSubscribe(t *testing.T) {
 			},
 		},
 		{
-			Name:   "existing client - authorized superuser",
+			Name:   "existing client - guest -> authorized superuser",
 			Method: http.MethodPost,
 			URL:    "/api/realtime",
 			Body:   strings.NewReader(`{"clientId":"` + client.Id() + `","subscriptions":["test1", "test2"]}`),
@@ -257,7 +257,7 @@ func TestRealtimeSubscribe(t *testing.T) {
 			},
 		},
 		{
-			Name:   "existing client - authorized regular record",
+			Name:   "existing client - guest -> authorized regular auth record",
 			Method: http.MethodPost,
 			URL:    "/api/realtime",
 			Body:   strings.NewReader(`{"clientId":"` + client.Id() + `","subscriptions":["test1", "test2"]}`),
@@ -280,6 +280,38 @@ func TestRealtimeSubscribe(t *testing.T) {
 				resetClient()
 			},
 		},
+		{
+			Name:   "existing client - same auth",
+			Method: http.MethodPost,
+			URL:    "/api/realtime",
+			Body:   strings.NewReader(`{"clientId":"` + client.Id() + `","subscriptions":["test1", "test2"]}`),
+			Headers: map[string]string{
+				"Authorization": "eyJhbGciOiJIUzI1NiJ9.eyJpZCI6IjRxMXhsY2xtZmxva3UzMyIsInR5cGUiOiJhdXRoIiwiY29sbGVjdGlvbklkIjoiX3BiX3VzZXJzX2F1dGhfIiwiZXhwIjoyNTI0NjA0NDYxLCJyZWZyZXNoYWJsZSI6dHJ1ZX0.ZT3F0Z3iM-xbGgSG3LEKiEzHrPHr8t8IuHLZGGNuxLo",
+			},
+			ExpectedStatus: 204,
+			ExpectedEvents: map[string]int{
+				"*":                          0,
+				"OnRealtimeSubscribeRequest": 1,
+			},
+			BeforeTestFunc: func(t testing.TB, app *tests.TestApp, e *core.ServeEvent) {
+				// the same user as the auth token
+				user, err := app.FindAuthRecordByEmail("users", "test@example.com")
+				if err != nil {
+					t.Fatal(err)
+				}
+
+				client.Set(apis.RealtimeClientAuthKey, user)
+
+				app.SubscriptionsBroker().Register(client)
+			},
+			AfterTestFunc: func(t testing.TB, app *tests.TestApp, res *http.Response) {
+				authRecord, _ := client.Get(apis.RealtimeClientAuthKey).(*core.Record)
+				if authRecord == nil {
+					t.Errorf("Expected auth record model, got nil")
+				}
+				resetClient()
+			},
+		},
 		{
 			Name:   "existing client - mismatched auth",
 			Method: http.MethodPost,