diff --git a/rslearn/tile_stores/__init__.py b/rslearn/tile_stores/__init__.py
index 670e56d..4cce29e 100644
--- a/rslearn/tile_stores/__init__.py
+++ b/rslearn/tile_stores/__init__.py
@@ -6,6 +6,7 @@
 from upath import UPath
 
 from rslearn.config import LayerConfig
+from rslearn.utils.jsonargparse import init_jsonargparse
 
 from .default import DefaultTileStore
 from .tile_store import TileStore, TileStoreWithLayer
@@ -32,6 +33,7 @@ def load_tile_store(config: dict[str, Any], ds_path: UPath) -> TileStore:
         tile_store.set_dataset_path(ds_path)
         return tile_store
 
+    init_jsonargparse()
     parser = jsonargparse.ArgumentParser()
     parser.add_argument("--tile_store", type=TileStore)
     cfg = parser.parse_object({"tile_store": config})
diff --git a/rslearn/utils/jsonargparse.py b/rslearn/utils/jsonargparse.py
new file mode 100644
index 0000000..e20d40d
--- /dev/null
+++ b/rslearn/utils/jsonargparse.py
@@ -0,0 +1,33 @@
+"""Custom serialization for jsonargparse."""
+
+import jsonargparse
+from rasterio.crs import CRS
+
+
+def crs_serializer(v: CRS) -> str:
+    """Serialize CRS for jsonargparse.
+
+    Args:
+        v: the CRS object.
+
+    Returns:
+        the CRS encoded to string
+    """
+    return v.to_string()
+
+
+def crs_deserializer(v: str) -> CRS:
+    """Deserialize CRS for jsonargparse.
+
+    Args:
+        v: the encoded CRS.
+
+    Returns:
+        the decoded CRS object
+    """
+    return CRS.from_string(v)
+
+
+def init_jsonargparse() -> None:
+    """Initialize custom jsonargparse serializers."""
+    jsonargparse.typing.register_type(CRS, crs_serializer, crs_deserializer)