diff --git a/jax/_src/array.py b/jax/_src/array.py
index 4f1bf3ea3..5226dc2a0 100644
--- a/jax/_src/array.py
+++ b/jax/_src/array.py
@@ -75,7 +75,7 @@ class Shard:
     except ValueError:
       return f'Shard(device={repr(self.device)}, data={self.data})'
 
-  @property
+  @functools.cached_property
   def index(self) -> Index:
     try:
       device_indices_map_fn = self._sharding.devices_indices_map
@@ -87,7 +87,7 @@ class Shard:
     assert index is not None
     return index
 
-  @property
+  @functools.cached_property
   def replica_id(self) -> int:
     return device_replica_id_map(self._sharding, self._global_shape)[self.device]