diff --git a/pkg/rtc/room.go b/pkg/rtc/room.go
index 94e66fac0..e7b4aaece 100644
--- a/pkg/rtc/room.go
+++ b/pkg/rtc/room.go
@@ -323,6 +323,14 @@ func (r *Room) ToProto() *livekit.Room {
 	return r.protoProxy.Get()
 }
 
+// ToProtoConsistent returns a room proto with participant counts computed
+// directly from the current participants map, bypassing the batched proto
+// proxy. Use this when an accurate num_participants is required immediately,
+// e.g. for webhook or telemetry events.
+func (r *Room) ToProtoConsistent() *livekit.Room {
+	return r.updateProto()
+}
+
 func (r *Room) Name() livekit.RoomName {
 	return livekit.RoomName(r.protoRoom.Name)
 }
@@ -1403,10 +1411,6 @@ func (r *Room) RemoveParticipant(
 	delete(r.participantRequestSources, identity)
 	delete(r.hasPublished, identity)
 	delete(r.agentParticpants, identity)
-	if !p.Hidden() {
-		r.protoRoom.NumParticipants--
-	}
-
 	immediateChange := false
 	if p.IsRecorder() {
 		activeRecording := false
diff --git a/pkg/service/roommanager.go b/pkg/service/roommanager.go
index 267324959..33bfac448 100644
--- a/pkg/service/roommanager.go
+++ b/pkg/service/roommanager.go
@@ -569,7 +569,8 @@ func (r *RoomManager) StartSession(
 	persistRoomForParticipantCount(room.ToProto())
 
 	clientMeta := &livekit.AnalyticsClientMeta{Region: r.currentNode.Region(), Node: string(r.currentNode.NodeID())}
-	r.telemetry.ParticipantJoined(ctx, protoRoom, participant.ToProto(), pi.Client, clientMeta, true, participant.TelemetryGuard())
+	// Use a consistent room proto so num_participants reflects the newly joined participant
+	r.telemetry.ParticipantJoined(ctx, room.ToProtoConsistent(), participant.ToProto(), pi.Client, clientMeta, true, participant.TelemetryGuard())
 	participant.AddOnClose(types.ParticipantCloseKeyNormal, func(p types.LocalParticipant) {
 		participantServerClosers.Close()
 
@@ -577,8 +578,8 @@ func (r *RoomManager) StartSession(
 			pLogger.Errorw("could not delete participant", err)
 		}
 
-		// update room store with new numParticipants
-		proto := room.ToProto()
+		// use consistent proto so num_participants is accurate for webhook
+		proto := room.ToProtoConsistent()
 		persistRoomForParticipantCount(proto)
 		r.telemetry.ParticipantLeft(ctx, proto, p.ToProto(), true, participant.TelemetryGuard())
 	})