diff --git a/src/adk_firestore_sessionmanager/firestore_session_service.py b/src/adk_firestore_sessionmanager/firestore_session_service.py
index 07f61d2..b9102ce 100644
--- a/src/adk_firestore_sessionmanager/firestore_session_service.py
+++ b/src/adk_firestore_sessionmanager/firestore_session_service.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import asyncio
 import logging
 import time
 from typing import Any, Optional
@@ -239,28 +240,38 @@ class FirestoreSessionService(BaseSessionService):
         user_state_delta = state_deltas["user"]
         session_state = state_deltas["session"]
 
+        write_coros: list = []
         if app_state_delta:
-            await self._app_state_ref(app_name).set(
-                app_state_delta, merge=True
+            write_coros.append(
+                self._app_state_ref(app_name).set(
+                    app_state_delta, merge=True
+                )
             )
         if user_state_delta:
-            await self._user_state_ref(app_name, user_id).set(
-                user_state_delta, merge=True
+            write_coros.append(
+                self._user_state_ref(app_name, user_id).set(
+                    user_state_delta, merge=True
+                )
             )
 
         now = time.time()
-        await self._session_ref(app_name, user_id, session_id).set(
-            {
-                "app_name": app_name,
-                "user_id": user_id,
-                "session_id": session_id,
-                "state": session_state or {},
-                "last_update_time": now,
-            }
+        write_coros.append(
+            self._session_ref(app_name, user_id, session_id).set(
+                {
+                    "app_name": app_name,
+                    "user_id": user_id,
+                    "session_id": session_id,
+                    "state": session_state or {},
+                    "last_update_time": now,
+                }
+            )
         )
+        await asyncio.gather(*write_coros)
 
-        app_state = await self._get_app_state(app_name)
-        user_state = await self._get_user_state(app_name, user_id)
+        app_state, user_state = await asyncio.gather(
+            self._get_app_state(app_name),
+            self._get_user_state(app_name, user_id),
+        )
         merged = self._merge_state(app_state, user_state, session_state or {})
 
         return Session(
@@ -293,7 +304,11 @@ class FirestoreSessionService(BaseSessionService):
             query = query.where(filter=FieldFilter("timestamp", ">=", config.after_timestamp))
         query = query.order_by("timestamp")
 
-        event_docs = await query.get()
+        event_docs, app_state, user_state = await asyncio.gather(
+            query.get(),
+            self._get_app_state(app_name),
+            self._get_user_state(app_name, user_id),
+        )
         events = [Event.model_validate(doc.to_dict()) for doc in event_docs]
 
         if config and config.num_recent_events:
@@ -341,8 +356,6 @@ class FirestoreSessionService(BaseSessionService):
             events = [summary_event, ack_event] + events
 
         # Merge scoped state
-        app_state = await self._get_app_state(app_name)
-        user_state = await self._get_user_state(app_name, user_id)
         merged = self._merge_state(
             app_state, user_state, session_data.get("state", {})
         )
@@ -370,22 +383,22 @@ class FirestoreSessionService(BaseSessionService):
         if not docs:
             return ListSessionsResponse()
 
-        # Pre-fetch app state (shared across all sessions in this app)
-        app_state = await self._get_app_state(app_name)
+        doc_dicts = [doc.to_dict() for doc in docs]
+
+        # Pre-fetch app state and all distinct user states in parallel
+        unique_user_ids = list({d["user_id"] for d in doc_dicts})
+        app_state, *user_states = await asyncio.gather(
+            self._get_app_state(app_name),
+            *(
+                self._get_user_state(app_name, uid)
+                for uid in unique_user_ids
+            ),
+        )
+        user_state_cache = dict(zip(unique_user_ids, user_states))
 
-        # Cache user states to avoid repeated reads
-        user_state_cache: dict[str, dict[str, Any]] = {}
         sessions: list[Session] = []
-
-        for doc in docs:
-            data = doc.to_dict()
+        for data in doc_dicts:
             s_user_id = data["user_id"]
-
-            if s_user_id not in user_state_cache:
-                user_state_cache[s_user_id] = await self._get_user_state(
-                    app_name, s_user_id
-                )
-
             merged = self._merge_state(
                 app_state,
                 user_state_cache[s_user_id],
@@ -442,13 +455,18 @@ class FirestoreSessionService(BaseSessionService):
                 event.actions.state_delta
             )
 
+            write_coros: list = []
             if state_deltas["app"]:
-                await self._app_state_ref(app_name).set(
-                    state_deltas["app"], merge=True
+                write_coros.append(
+                    self._app_state_ref(app_name).set(
+                        state_deltas["app"], merge=True
+                    )
                 )
             if state_deltas["user"]:
-                await self._user_state_ref(app_name, user_id).set(
-                    state_deltas["user"], merge=True
+                write_coros.append(
+                    self._user_state_ref(app_name, user_id).set(
+                        state_deltas["user"], merge=True
+                    )
                 )
 
             if state_deltas["session"]:
@@ -457,11 +475,13 @@ class FirestoreSessionService(BaseSessionService):
                     for k, v in state_deltas["session"].items()
                 }
                 field_updates["last_update_time"] = event.timestamp
-                await session_ref.update(field_updates)
+                write_coros.append(session_ref.update(field_updates))
             else:
-                await session_ref.update(
-                    {"last_update_time": event.timestamp}
+                write_coros.append(
+                    session_ref.update({"last_update_time": event.timestamp})
                 )
+
+            await asyncio.gather(*write_coros)
         else:
             await session_ref.update({"last_update_time": event.timestamp})