diff --git a/CHANGELOG.md b/CHANGELOG.md
index 326c337933..a0009e8cb7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
 # Unreleased
 
+* Fix: captureTransaction should return emptyId when transaction is discarded (#713)
+
 # 6.3.0-beta.3
 
 * Feat: Auto transactions duration trimming (#702)
diff --git a/dart/lib/src/sentry_client.dart b/dart/lib/src/sentry_client.dart
index a976b9b3d7..6e0a870627 100644
--- a/dart/lib/src/sentry_client.dart
+++ b/dart/lib/src/sentry_client.dart
@@ -261,7 +261,7 @@ class SentryClient {
 
     final id = await captureEnvelope(
         SentryEnvelope.fromTransaction(preparedTransaction, _options.sdk));
-    return id!;
+    return id ?? SentryId.empty();
   }
 
   /// Reports the [envelope] to Sentry.io.
diff --git a/dart/test/sentry_client_test.dart b/dart/test/sentry_client_test.dart
index 6a9c6fdf31..b6d39958a0 100644
--- a/dart/test/sentry_client_test.dart
+++ b/dart/test/sentry_client_test.dart
@@ -346,6 +346,14 @@ void main() {
 
       expect(capturedEvent['exception'], isNull);
     });
+
+    test('should return empty for when transaction is discarded', () async {
+      final client = fixture.getSut(eventProcessor: DropAllEventProcessor());
+      final tr = SentryTransaction(fixture.tracer);
+      final id = await client.captureTransaction(tr);
+
+      expect(id, SentryId.empty());
+    });
   });
 
   group('SentryClient : apply scope to the captured event', () {