diff --git a/airbyte-integrations/connectors/source-s3/metadata.yaml b/airbyte-integrations/connectors/source-s3/metadata.yaml
index 1191a956bbf4..14871c0b58e3 100644
--- a/airbyte-integrations/connectors/source-s3/metadata.yaml
+++ b/airbyte-integrations/connectors/source-s3/metadata.yaml
@@ -10,7 +10,7 @@ data:
   connectorSubtype: file
   connectorType: source
   definitionId: 69589781-7828-43c5-9f63-8925b1c1ccc2
-  dockerImageTag: 4.15.4
+  dockerImageTag: 4.15.5
   dockerRepository: airbyte/source-s3
   documentationUrl: https://docs.airbyte.com/integrations/sources/s3
   externalDocumentationUrls:
diff --git a/airbyte-integrations/connectors/source-s3/poetry.lock b/airbyte-integrations/connectors/source-s3/poetry.lock
index fd9311ae85b6..35ca06161b1b 100644
--- a/airbyte-integrations/connectors/source-s3/poetry.lock
+++ b/airbyte-integrations/connectors/source-s3/poetry.lock
@@ -2,14 +2,14 @@
 
 [[package]]
 name = "airbyte-cdk"
-version = "7.19.1"
+version = "7.19.2"
 description = "A framework for writing Airbyte Connectors."
 optional = false
 python-versions = "<3.14,>=3.10"
 groups = ["main"]
 files = [
-    {file = "airbyte_cdk-7.19.1-py3-none-any.whl", hash = "sha256:982410e582174cda84a3424c783c65dca38b4370ecaf660ac5c6c8b2b298c273"},
-    {file = "airbyte_cdk-7.19.1.tar.gz", hash = "sha256:882b127409193f329d91f8d9671f385d5a6b3440ee333ebfd5d235b3947eb7d8"},
+    {file = "airbyte_cdk-7.19.2-py3-none-any.whl", hash = "sha256:3ff64c854e2b04351037def1e92bd105affb459bc8333d35631b58f5d06982d0"},
+    {file = "airbyte_cdk-7.19.2.tar.gz", hash = "sha256:9d55df2cfbb21d83b9b98d66784e9409e753e8f62afaea2cfbbfb56a22dc00fc"},
 ]
 
 [package.dependencies]
diff --git a/airbyte-integrations/connectors/source-s3/pyproject.toml b/airbyte-integrations/connectors/source-s3/pyproject.toml
index a4048cec6f33..1a2e70cfc56d 100644
--- a/airbyte-integrations/connectors/source-s3/pyproject.toml
+++ b/airbyte-integrations/connectors/source-s3/pyproject.toml
@@ -3,7 +3,7 @@ requires = [ "poetry-core>=1.0.0",]
 build-backend = "poetry.core.masonry.api"
 
 [tool.poetry]
-version = "4.15.4"
+version = "4.15.5"
 name = "source-s3"
 description = "Source implementation for S3."
 authors = [ "Airbyte <contact@airbyte.io>",]
diff --git a/airbyte-integrations/connectors/source-s3/source_s3/v4/__init__.py b/airbyte-integrations/connectors/source-s3/source_s3/v4/__init__.py
index 0869a3773d36..2c96d9029534 100644
--- a/airbyte-integrations/connectors/source-s3/source_s3/v4/__init__.py
+++ b/airbyte-integrations/connectors/source-s3/source_s3/v4/__init__.py
@@ -8,4 +8,5 @@
 from .source import SourceS3
 from .stream_reader import SourceS3StreamReader
 
+
 __all__ = ["Config", "Cursor", "LegacyConfigTransformer", "SourceS3", "SourceS3StreamReader"]
diff --git a/airbyte-integrations/connectors/source-s3/unit_tests/v4/test_source.py b/airbyte-integrations/connectors/source-s3/unit_tests/v4/test_source.py
index 04a23079910b..d7b81be1ad96 100644
--- a/airbyte-integrations/connectors/source-s3/unit_tests/v4/test_source.py
+++ b/airbyte-integrations/connectors/source-s3/unit_tests/v4/test_source.py
@@ -8,6 +8,15 @@
 
 from source_s3.v4 import Config, SourceS3, SourceS3StreamReader
 
+from airbyte_cdk.models import AirbyteStream, SyncMode
+from airbyte_cdk.sources.concurrent_source.concurrent_read_processor import ConcurrentReadProcessor
+from airbyte_cdk.sources.concurrent_source.thread_pool_manager import ThreadPoolManager
+from airbyte_cdk.sources.message import MessageRepository
+from airbyte_cdk.sources.streams.concurrent.abstract_stream import AbstractStream
+from airbyte_cdk.sources.streams.concurrent.partition_enqueuer import PartitionEnqueuer
+from airbyte_cdk.sources.streams.concurrent.partition_reader import PartitionReader
+from airbyte_cdk.sources.utils.slice_logger import SliceLogger
+
 
 _V3_FIELDS = ["dataset", "format", "path_pattern", "provider", "schema"]
 TEST_FILES_FOLDER = Path(__file__).resolve().parent.parent.joinpath("sample_files")
@@ -52,3 +61,31 @@ def test_when_spec_then_v3_fields_descriptions_are_prefixed_with_deprecation_war
     def test_when_spec_then_v3_nested_fields_are_not_required(self) -> None:
         spec = self._source.spec()
         assert not spec.connectionSpecification["properties"]["provider"]["required"]
+
+
+def test_airbyte_cdk_limits_concurrent_partition_generators() -> None:
+    stream = Mock(spec=AbstractStream)
+    stream.name = "stream"
+    stream.block_simultaneous_read = ""
+    stream.as_airbyte_stream.return_value = AirbyteStream(
+        name="stream",
+        json_schema={},
+        supported_sync_modes=[SyncMode.full_refresh],
+    )
+    thread_pool_manager = Mock(spec=ThreadPoolManager)
+    handler = ConcurrentReadProcessor(
+        [stream],
+        Mock(spec=PartitionEnqueuer),
+        thread_pool_manager,
+        Mock(),
+        Mock(spec=SliceLogger),
+        Mock(spec=MessageRepository),
+        Mock(spec=PartitionReader),
+        max_concurrent_partition_generators=1,
+    )
+    handler._streams_currently_generating_partitions.append("active_stream")
+
+    status_message = handler.start_next_partition_generator()
+
+    assert status_message is None
+    thread_pool_manager.submit.assert_not_called()
diff --git a/docs/integrations/sources/s3.md b/docs/integrations/sources/s3.md
index a3c4522f5b48..8566d892e60e 100644
--- a/docs/integrations/sources/s3.md
+++ b/docs/integrations/sources/s3.md
@@ -356,6 +356,7 @@ This connector utilizes the open source [Unstructured](https://unstructured-io.g
 
 | Version     | Date       | Pull Request                                                                                                    | Subject                                                                                                              |
 |:------------|:-----------|:----------------------------------------------------------------------------------------------------------------|:---------------------------------------------------------------------------------------------------------------------|
+| 4.15.5 | 2026-05-20 | [TBD](https://github.com/airbytehq/airbyte/pull/TBD) | Improved completion reliability for large full refresh syncs. |
 | 4.15.4 | 2026-05-14 | [78081](https://github.com/airbytehq/airbyte/pull/78081) | Updates the source-s3 Poetry lock file to use airbyte-cdk 7.19.1 for CSV column error. |
 | 4.15.3 | 2026-04-08 | [76162](https://github.com/airbytehq/airbyte/pull/76162) | Add opt-in `skip_full_check_for_parquet` stream option to skip the full parse check for Parquet files during CHECK, avoiding OOM on large files |
 | 4.15.2 | 2025-11-11 | [69268](https://github.com/airbytehq/airbyte/pull/69268) | Update dependencies |