diff --git a/src/google/adk/sessions/_session_util.py b/src/google/adk/sessions/_session_util.py
index 2fc0c811d8..6f7335c6fa 100644
--- a/src/google/adk/sessions/_session_util.py
+++ b/src/google/adk/sessions/_session_util.py
@@ -44,6 +44,17 @@ def decode_model(data: object | None, model_cls: type[M]) -> M | None:
   return model_cls.model_validate(data)
 
 
+def normalize_session_id(session_id: str | None) -> str | None:
+  """Normalizes a session id so that writes and reads agree on the key.
+
+  Ids often arrive from files, environment variables or spreadsheet cells with
+  surrounding whitespace. Every entry point must apply the same normalization,
+  otherwise a session created with a padded id cannot be read or deleted with
+  that same id.
+  """
+  return session_id.strip() if session_id else session_id
+
+
 def extract_state_delta(
     state: dict[str, Any],
 ) -> dict[str, dict[str, Any]]:
diff --git a/src/google/adk/sessions/in_memory_session_service.py b/src/google/adk/sessions/in_memory_session_service.py
index e7613e8f50..ee07ab302b 100644
--- a/src/google/adk/sessions/in_memory_session_service.py
+++ b/src/google/adk/sessions/in_memory_session_service.py
@@ -114,7 +114,7 @@ def _create_session_impl(
       state: Optional[dict[str, Any]] = None,
       session_id: Optional[str] = None,
   ) -> Session:
-    session_id = session_id.strip() if session_id else None
+    session_id = _session_util.normalize_session_id(session_id)
     if session_id and self._get_session_impl(
         app_name=app_name, user_id=user_id, session_id=session_id
     ):
@@ -188,6 +188,7 @@ def _get_session_impl(
       session_id: str,
       config: Optional[GetSessionConfig] = None,
   ) -> Optional[Session]:
+    session_id = _session_util.normalize_session_id(session_id)
     if app_name not in self.sessions:
       return None
     if user_id not in self.sessions[app_name]:
@@ -303,6 +304,7 @@ def delete_session_sync(
   def _delete_session_impl(
       self, *, app_name: str, user_id: str, session_id: str
   ) -> None:
+    session_id = _session_util.normalize_session_id(session_id)
     if (
         self._get_session_impl(
             app_name=app_name, user_id=user_id, session_id=session_id
diff --git a/src/google/adk/sessions/sqlite_session_service.py b/src/google/adk/sessions/sqlite_session_service.py
index e40eb08768..0922d2b9f0 100644
--- a/src/google/adk/sessions/sqlite_session_service.py
+++ b/src/google/adk/sessions/sqlite_session_service.py
@@ -206,8 +206,7 @@ async def create_session(
       state: Optional[dict[str, Any]] = None,
       session_id: Optional[str] = None,
   ) -> Session:
-    if session_id:
-      session_id = session_id.strip()
+    session_id = _session_util.normalize_session_id(session_id)
     if not session_id:
       session_id = platform_uuid.new_uuid()
     now = platform_time.get_time()
@@ -280,6 +279,7 @@ async def get_session(
       session_id: str,
       config: Optional[GetSessionConfig] = None,
   ) -> Optional[Session]:
+    session_id = _session_util.normalize_session_id(session_id)
     async with self._get_db_connection() as db:
       async with db.execute(
           "SELECT state, update_time FROM sessions WHERE app_name=? AND"
@@ -403,6 +403,7 @@ async def list_sessions(
   async def delete_session(
       self, *, app_name: str, user_id: str, session_id: str
   ) -> None:
+    session_id = _session_util.normalize_session_id(session_id)
     async with self._get_db_connection() as db:
       await db.execute(
           "DELETE FROM sessions WHERE app_name=? AND user_id=? AND id=?",
diff --git a/tests/unittests/sessions/test_session_service.py b/tests/unittests/sessions/test_session_service.py
index 9148eab8e0..df8205cd51 100644
--- a/tests/unittests/sessions/test_session_service.py
+++ b/tests/unittests/sessions/test_session_service.py
@@ -1227,6 +1227,46 @@ async def test_create_session_with_padded_duplicate_id_raises_error():
   assert session.state['keep'] == 'original'
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    'service_type',
+    [SessionServiceType.IN_MEMORY, SessionServiceType.SQLITE],
+)
+async def test_padded_session_id_reads_and_deletes(service_type, tmp_path):
+  """Tests that the id normalization applied on create also applies on read
+  and delete, so a caller passing one padded id throughout keeps reaching the
+  session it created."""
+  service = get_session_service(service_type, tmp_path)
+  app_name = 'my_app'
+  user_id = 'test_user'
+  padded_id = 'order-42\n'
+
+  created = await service.create_session(
+      app_name=app_name,
+      user_id=user_id,
+      session_id=padded_id,
+      state={'cart': 'book'},
+  )
+  assert created.id == 'order-42'
+
+  session = await service.get_session(
+      app_name=app_name, user_id=user_id, session_id=padded_id
+  )
+  assert session is not None
+  assert session.id == 'order-42'
+  assert session.state['cart'] == 'book'
+
+  await service.delete_session(
+      app_name=app_name, user_id=user_id, session_id=padded_id
+  )
+  assert (
+      await service.get_session(
+          app_name=app_name, user_id=user_id, session_id='order-42'
+      )
+      is None
+  )
+
+
 @pytest.mark.asyncio
 async def test_create_session_with_blank_id_generates_one():
   """Tests that a whitespace-only session id is treated the same as no id
diff --git a/tests/unittests/sessions/test_session_util.py b/tests/unittests/sessions/test_session_util.py
index 28b79e9eb2..d753653baa 100644
--- a/tests/unittests/sessions/test_session_util.py
+++ b/tests/unittests/sessions/test_session_util.py
@@ -25,6 +25,7 @@
 from google.adk.sessions._session_util import decode_model
 from google.adk.sessions._session_util import extract_state_delta
 from google.adk.sessions._session_util import make_json_safe_state
+from google.adk.sessions._session_util import normalize_session_id
 from google.genai import types
 from pydantic import BaseModel
 import pytest
@@ -62,6 +63,22 @@ class _SampleModel(BaseModel):
       decode_model({"name": "foo"}, _SampleModel)
 
 
+class TestNormalizeSessionId:
+  """Tests for normalize_session_id utility."""
+
+  def test_strips_surrounding_whitespace(self):
+    """An id padded by a file or CSV cell normalizes to its trimmed form."""
+    assert normalize_session_id("  order-42\n") == "order-42"
+
+  def test_maps_whitespace_only_id_to_a_falsy_value(self):
+    """A whitespace-only id is as good as no id, so callers can generate one."""
+    assert not normalize_session_id("   ")
+
+  def test_passes_none_through(self):
+    """A missing id stays missing rather than becoming an empty string."""
+    assert normalize_session_id(None) is None
+
+
 class TestExtractStateDelta:
   """Tests for extract_state_delta utility."""