diff --git a/changelog/3765.changed.md b/changelog/3765.changed.md
new file mode 100644
index 000000000..5d3e758d5
--- /dev/null
+++ b/changelog/3765.changed.md
@@ -0,0 +1 @@
+- Updated `InworldTTSService` and `InworldHttpTTSService` to use `ASYNC` timestamp transport strategy by default
diff --git a/src/pipecat/services/inworld/tts.py b/src/pipecat/services/inworld/tts.py
index 9f7c0cff1..9767c1b0a 100644
--- a/src/pipecat/services/inworld/tts.py
+++ b/src/pipecat/services/inworld/tts.py
@@ -70,7 +70,7 @@ class InworldHttpTTSService(WordTTSService):
 
         temperature: Optional[float] = None
         speaking_rate: Optional[float] = None
-        timestamp_transport_strategy: Optional[Literal["ASYNC", "SYNC"]] = None
+        timestamp_transport_strategy: Optional[Literal["ASYNC", "SYNC"]] = "ASYNC"
 
     def __init__(
         self,
@@ -442,7 +442,7 @@ class InworldTTSService(AudioContextWordTTSService):
         max_buffer_delay_ms: Optional[int] = None
         buffer_char_threshold: Optional[int] = None
         auto_mode: Optional[bool] = True
-        timestamp_transport_strategy: Optional[Literal["ASYNC", "SYNC"]] = None
+        timestamp_transport_strategy: Optional[Literal["ASYNC", "SYNC"]] = "ASYNC"
 
     def __init__(
         self,