diff --git a/core/sync/__init__.py b/core/sync/__init__.py
index 8c65add6..adf149e0 100644
--- a/core/sync/__init__.py
+++ b/core/sync/__init__.py
@@ -1,7 +1,8 @@
 """Edge/cloud sync contracts for CORE.
 
 This package is intentionally pure at import time: no concrete object-store
-client, no network dependency, and no hot-path integration.
+client, no network dependency, and no hot-path integration.  Concrete S3 support
+is optional and lazy-imports provider SDKs only when constructed.
 """
 
 from core.sync.activation import ActivationDecision, ActivationLedger, ActivationRecord
@@ -20,6 +21,7 @@ from core.sync.journal import (
 )
 from core.sync.manifest import ManifestCheck, SyncManifest, parse_manifest, validate_manifest
 from core.sync.object_store import ObjectMetadata, ObjectNotFoundError, ObjectStore, ObjectStoreError
+from core.sync.s3_store import S3ObjectStore
 
 __all__ = [
     "ARTIFACT_AUTHORITY",
@@ -38,6 +40,7 @@ __all__ = [
     "ObjectNotFoundError",
     "ObjectStore",
     "ObjectStoreError",
+    "S3ObjectStore",
     "SyncManifest",
     "authority_for",
     "parse_manifest",