diff --git a/airbyte_cdk/sources/concurrent_source/concurrent_source.py b/airbyte_cdk/sources/concurrent_source/concurrent_source.py
index de2d93523..ea020a14d 100644
--- a/airbyte_cdk/sources/concurrent_source/concurrent_source.py
+++ b/airbyte_cdk/sources/concurrent_source/concurrent_source.py
@@ -99,7 +99,7 @@ def __init__(
         # threads generating partitions that than are max number of workers. If it weren't the case, we could have threads only generating
         # partitions which would fill the queue. This number is arbitrarily set to 10_000 but will probably need to be changed given more
         # information and might even need to be configurable depending on the source
-        self._queue = queue or Queue(maxsize=10_000)
+        self._queue = queue or Queue(maxsize=0)
 
     def read(
         self,
diff --git a/airbyte_cdk/sources/declarative/concurrent_declarative_source.py b/airbyte_cdk/sources/declarative/concurrent_declarative_source.py
index 45fe6aa2d..c769235dd 100644
--- a/airbyte_cdk/sources/declarative/concurrent_declarative_source.py
+++ b/airbyte_cdk/sources/declarative/concurrent_declarative_source.py
@@ -157,7 +157,7 @@ def __init__(
         # threads generating partitions that than are max number of workers. If it weren't the case, we could have threads only generating
         # partitions which would fill the queue. This number is arbitrarily set to 10_000 but will probably need to be changed given more
         # information and might even need to be configurable depending on the source
-        queue: Queue[QueueItem] = Queue(maxsize=10_000)
+        queue: Queue[QueueItem] = Queue(maxsize=0)
         message_repository = InMemoryMessageRepository(
             Level.DEBUG if emit_connector_builder_messages else Level.INFO
         )