diff --git a/durabletask/entities/entity_instance_id.py b/durabletask/entities/entity_instance_id.py
index c3b76c1..02a2595 100644
--- a/durabletask/entities/entity_instance_id.py
+++ b/durabletask/entities/entity_instance_id.py
@@ -1,6 +1,3 @@
-from typing import Optional
-
-
 class EntityInstanceId:
     def __init__(self, entity: str, key: str):
         self.entity = entity
@@ -20,7 +17,7 @@ def __lt__(self, other):
         return str(self) < str(other)
 
     @staticmethod
-    def parse(entity_id: str) -> Optional["EntityInstanceId"]:
+    def parse(entity_id: str) -> "EntityInstanceId":
         """Parse a string representation of an entity ID into an EntityInstanceId object.
 
         Parameters
@@ -30,8 +27,13 @@ def parse(entity_id: str) -> Optional["EntityInstanceId"]:
 
         Returns
         -------
-        Optional[EntityInstanceId]
-            The parsed EntityInstanceId object, or None if the input is None.
+        EntityInstanceId
+            The parsed EntityInstanceId object.
+
+        Raises
+        ------
+        ValueError
+            If the input string is not in the correct format.
         """
         try:
             _, entity, key = entity_id.split("@", 2)
diff --git a/durabletask/entities/entity_metadata.py b/durabletask/entities/entity_metadata.py
index 6800939..3e04206 100644
--- a/durabletask/entities/entity_metadata.py
+++ b/durabletask/entities/entity_metadata.py
@@ -44,8 +44,9 @@ def __init__(self,
 
     @staticmethod
     def from_entity_response(entity_response: pb.GetEntityResponse, includes_state: bool):
-        entity_id = EntityInstanceId.parse(entity_response.entity.instanceId)
-        if not entity_id:
+        try:
+            entity_id = EntityInstanceId.parse(entity_response.entity.instanceId)
+        except ValueError:
             raise ValueError("Invalid entity instance ID in entity response.")
         entity_state = None
         if includes_state:
diff --git a/durabletask/worker.py b/durabletask/worker.py
index fae345c..0c05430 100644
--- a/durabletask/worker.py
+++ b/durabletask/worker.py
@@ -750,9 +750,10 @@ def _execute_entity_batch(
         for operation in req.operations:
             start_time = datetime.now(timezone.utc)
             executor = _EntityExecutor(self._registry, self._logger)
-            entity_instance_id = EntityInstanceId.parse(instance_id)
-            if not entity_instance_id:
-                raise RuntimeError(f"Invalid entity instance ID '{operation.requestId}' in entity operation request.")
+            try:
+                entity_instance_id = EntityInstanceId.parse(instance_id)
+            except ValueError:
+                raise RuntimeError(f"Invalid entity instance ID '{instance_id}' in entity operation request.")
 
             operation_result = None
 
@@ -1656,8 +1657,9 @@ def process_event(
                     raise _get_wrong_action_type_error(
                         entity_call_id, expected_method_name, action
                     )
-                entity_id = EntityInstanceId.parse(event.entityOperationCalled.targetInstanceId.value)
-                if not entity_id:
+                try:
+                    entity_id = EntityInstanceId.parse(event.entityOperationCalled.targetInstanceId.value)
+                except ValueError:
                     raise RuntimeError(f"Could not parse entity ID from targetInstanceId '{event.entityOperationCalled.targetInstanceId.value}'")
                 ctx._entity_task_id_map[event.entityOperationCalled.requestId] = (entity_id, entity_call_id)
             elif event.HasField("entityOperationSignaled"):