diff --git a/src/hexkit/protocols/objstorage.py b/src/hexkit/protocols/objstorage.py
index 5328740b..fbaa3e91 100644
--- a/src/hexkit/protocols/objstorage.py
+++ b/src/hexkit/protocols/objstorage.py
@@ -489,7 +489,7 @@ async def _delete_object(self, *, bucket_id: str, object_id: str) -> None:
     # (is typically only used by the protocol but may also be used in
     # provider-specific code or overwritten by the provider)
 
-    _re_bucket_id = re.compile(r"^[:a-z0-9\-]{3,63}$")
+    _re_bucket_id = re.compile(r"^[a-z0-9\-]{3,63}$")
     _re_bucket_id_msg = "must consist of 3-63 lowercase letters, digits or hyphens"
 
     @classmethod
diff --git a/src/hexkit/providers/s3/provider.py b/src/hexkit/providers/s3/provider.py
index e9fe63b1..c7d50bf6 100644
--- a/src/hexkit/providers/s3/provider.py
+++ b/src/hexkit/providers/s3/provider.py
@@ -42,7 +42,9 @@
 
 __all__ = ["ObjectStorageProtocol", "PresignedPostURL"]
 # Allow colon character in bucket names to accommodate Ceph multi tenancy S3
-botocore.handlers.VALID_BUCKET = re.compile(r"^[:a-zA-Z0-9.\-_]{1,255}$")
+botocore.handlers.VALID_BUCKET = re.compile(
+    r"^(?:[a-zA-Z0-9_]{1,191}:)?[a-z0-9\-]{3,63}$"
+)
 
 
 class S3Config(BaseSettings):
@@ -120,6 +122,8 @@ def read_aws_config_ini(aws_config_ini: Path) -> botocore.config.Config:
 class S3ObjectStorage(ObjectStorageProtocol):
     """S3-based provider implementing the ObjectStorageProtocol."""
 
+    _re_bucket_id = botocore.handlers.VALID_BUCKET
+
     def __init__(
         self,
         *,
diff --git a/tests/integration/test_s3.py b/tests/integration/test_s3.py
index ea87d9dc..e0a1b262 100644
--- a/tests/integration/test_s3.py
+++ b/tests/integration/test_s3.py
@@ -105,6 +105,19 @@ async def test_object_existence_checks(s3: S3Fixture, tmp_file: FileObject):  #
     )
 
 
+async def test_bucket_name_with_tenant(s3: S3Fixture):
+    """Test if bucket names containing a tenant work correctly."""
+    check_bucket = s3.storage.does_bucket_exist
+    assert not await check_bucket("non-existing-bucket")
+    assert not await check_bucket("tenant:non-existing-bucket")
+    with pytest.raises(ObjectStorageProtocol.BucketIdValidationError):
+        assert not await check_bucket("tenant:invalid:bucket")
+    with pytest.raises(ObjectStorageProtocol.BucketIdValidationError):
+        assert not await check_bucket("tenant-invalid:bucket-valid")
+    with pytest.raises(ObjectStorageProtocol.BucketIdValidationError):
+        assert not await check_bucket("tenant_valid:bucket_invalid")
+
+
 async def test_get_object_etag(s3: S3Fixture, tmp_file: FileObject):  # noqa: F811
     """Test ETag retrieval."""
     await s3.populate_file_objects([tmp_file])