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/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/source.py b/airbyte-integrations/connectors/source-s3/source_s3/v4/source.py
index 2a0b1a66ba8a..b31b737f4d5e 100644
--- a/airbyte-integrations/connectors/source-s3/source_s3/v4/source.py
+++ b/airbyte-integrations/connectors/source-s3/source_s3/v4/source.py
@@ -27,7 +27,7 @@
     TraceType,
     Type,
 )
-from airbyte_cdk.sources.file_based.file_based_source import DEFAULT_CONCURRENCY, FileBasedSource
+from airbyte_cdk.sources.file_based.file_based_source import FileBasedSource
 from source_s3.source import SourceS3Spec
 from source_s3.utils import airbyte_message_to_json
 from source_s3.v4.availability_strategy import SourceS3AvailabilityStrategy
@@ -47,7 +47,7 @@
 
 
 class SourceS3(FileBasedSource):
-    _concurrency_level = DEFAULT_CONCURRENCY
+    _concurrency_level = 20
 
     @classmethod
     def read_config(cls, config_path: str) -> Mapping[str, Any]:
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..324b1f4d472b 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
@@ -52,3 +52,6 @@ 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_concurrency_level_is_capped(self) -> None:
+        assert SourceS3._concurrency_level == 20
diff --git a/docs/integrations/sources/s3.md b/docs/integrations/sources/s3.md
index a3c4522f5b48..864ad0883898 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 | 2026-05-25 | [78416](https://github.com/airbytehq/airbyte/pull/78416) | Cap concurrent file readers at 20 to prevent OOM on large S3 streams. |
 | 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 |