diff --git a/packages/segment-session-replay-plugin-react-native/src/segment-session-replay-plugin.ts b/packages/segment-session-replay-plugin-react-native/src/segment-session-replay-plugin.ts
index 742ff1a8cb..0788127567 100644
--- a/packages/segment-session-replay-plugin-react-native/src/segment-session-replay-plugin.ts
+++ b/packages/segment-session-replay-plugin-react-native/src/segment-session-replay-plugin.ts
@@ -2,6 +2,7 @@ import { Plugin, PluginType, type SegmentEvent, EventType, SegmentClient } from
 
 import {
   type SessionReplayConfig,
+  getSessionId as getSRSessionId,
   getSessionReplayProperties,
   init,
   setDeviceId,
@@ -41,6 +42,10 @@ export class SegmentSessionReplayPlugin extends Plugin {
   // because `configure` is not asynchronous
   private initPromise: Promise<void> | null = null;
 
+  // True when start() was called but deferred because no valid session ID (> 0)
+  // was available yet.  Flushed by execute() once a valid id arrives.
+  private pendingStart = false;
+
   constructor(config: SessionReplayConfig) {
     super();
     this.sessionReplayConfig = config;
@@ -64,6 +69,16 @@ export class SegmentSessionReplayPlugin extends Plugin {
     await setSessionId(sessionId);
     await setDeviceId(deviceId);
 
+    // Flush a deferred start() once the first valid session ID arrives.
+    // start() may have been called before any event flowed through here, at
+    // which point the native SDK's session ID was still -1 (the default
+    // sentinel).  We wait until we have a real id (> 0) before starting
+    // native recording to avoid corrupting the replay with sessionId -1.
+    if (this.pendingStart && sessionId > 0) {
+      this.pendingStart = false;
+      await start();
+    }
+
     if (event.type === EventType.TrackEvent || event.type === EventType.ScreenEvent) {
       const properties = await getSessionReplayProperties();
       event.properties = { ...event.properties, ...properties };
@@ -79,7 +94,16 @@ export class SegmentSessionReplayPlugin extends Plugin {
 
   async start(): Promise<void> {
     await this.initPromise;
-    await start();
+    // The native SDK defaults sessionId to -1 until the first Segment event
+    // flows through execute() and calls setSessionId() with a real value.
+    // Starting under -1 would tag the entire recording with an invalid session,
+    // so we defer if the current id is not yet valid (> 0).
+    const currentSessionId = await getSRSessionId();
+    if (currentSessionId !== null && currentSessionId > 0) {
+      await start();
+    } else {
+      this.pendingStart = true;
+    }
   }
 
   async stop(): Promise<void> {
diff --git a/packages/segment-session-replay-plugin-react-native/test/segment-session-replay-plugin.test.ts b/packages/segment-session-replay-plugin-react-native/test/segment-session-replay-plugin.test.ts
index 092b8d62f3..a02a9143d9 100644
--- a/packages/segment-session-replay-plugin-react-native/test/segment-session-replay-plugin.test.ts
+++ b/packages/segment-session-replay-plugin-react-native/test/segment-session-replay-plugin.test.ts
@@ -34,6 +34,7 @@ import {
   init,
   setDeviceId,
   setSessionId,
+  getSessionId,
   getSessionReplayProperties,
   start,
   stop,
@@ -45,6 +46,7 @@ jest.mock('@amplitude/session-replay-react-native', () => ({
   init: jest.fn(),
   setDeviceId: jest.fn(),
   setSessionId: jest.fn(),
+  getSessionId: jest.fn(),
   getSessionReplayProperties: jest.fn(),
   start: jest.fn(),
   stop: jest.fn(),
@@ -58,6 +60,9 @@ describe('SegmentSessionReplayPlugin', () => {
   beforeEach(() => {
     jest.clearAllMocks();
 
+    // Default: native SDK has not yet received a real session ID (the -1 sentinel).
+    (getSessionId as jest.Mock).mockResolvedValue(-1);
+
     mockConfig = {
       apiKey: 'test-api-key',
     };
@@ -266,9 +271,85 @@ describe('SegmentSessionReplayPlugin', () => {
   });
 
   describe('start', () => {
-    it('should call start', async () => {
+    it('should call native start immediately when a valid session ID already exists', async () => {
+      (getSessionId as jest.Mock).mockResolvedValue(1700000000000);
+
+      await plugin.start();
+
+      expect(start).toHaveBeenCalledTimes(1);
+    });
+
+    it('should NOT call native start when session ID is -1 (autoStart:false bug)', async () => {
+      // SR SDK still has the default -1 sentinel — no real session ID yet.
+      (getSessionId as jest.Mock).mockResolvedValue(-1);
+
+      await plugin.start();
+
+      expect(start).not.toHaveBeenCalled();
+    });
+
+    it('should NOT call native start when session ID is null', async () => {
+      (getSessionId as jest.Mock).mockResolvedValue(null);
+
+      await plugin.start();
+
+      expect(start).not.toHaveBeenCalled();
+    });
+
+    it('should flush deferred start on the first execute() with a valid session ID', async () => {
+      // Simulate autoStart:false → start() before any event
+      (getSessionId as jest.Mock).mockResolvedValue(-1);
       await plugin.start();
-      expect(start).toHaveBeenCalled();
+      expect(start).not.toHaveBeenCalled();
+
+      // First real event arrives carrying the actual session ID
+      const mockEvent: SegmentEvent = {
+        type: EventType.TrackEvent,
+        event: 'app_opened',
+        properties: { session_id: '1700000000000' },
+        context: { device: { id: 'device-abc' } },
+      } as any;
+      (getSessionReplayProperties as jest.Mock).mockResolvedValue({});
+
+      await plugin.execute(mockEvent);
+
+      // Native start() should now have been called exactly once with the real id.
+      expect(start).toHaveBeenCalledTimes(1);
+    });
+
+    it('should NOT flush deferred start when execute() carries sessionId -1', async () => {
+      (getSessionId as jest.Mock).mockResolvedValue(-1);
+      await plugin.start();
+
+      const mockEvent: SegmentEvent = {
+        type: EventType.TrackEvent,
+        event: 'no_session_yet',
+        properties: {},
+        context: {},
+      } as any;
+      (getSessionReplayProperties as jest.Mock).mockResolvedValue({});
+
+      await plugin.execute(mockEvent);
+
+      expect(start).not.toHaveBeenCalled();
+    });
+
+    it('should flush deferred start only once across multiple execute() calls', async () => {
+      (getSessionId as jest.Mock).mockResolvedValue(-1);
+      await plugin.start();
+
+      const eventWithSession: SegmentEvent = {
+        type: EventType.TrackEvent,
+        event: 'button_clicked',
+        properties: { session_id: '1700000000000' },
+        context: { device: { id: 'device-abc' } },
+      } as any;
+      (getSessionReplayProperties as jest.Mock).mockResolvedValue({});
+
+      await plugin.execute(eventWithSession);
+      await plugin.execute(eventWithSession);
+
+      expect(start).toHaveBeenCalledTimes(1);
     });
   });