diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9d08974c..e2989247 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 ### Added
+-   Log observation space data by episode and step.
+
+## [3.3.0] - 2024-09-04
+### Added
 -   Random Number Generator Seeding by specifying a random number seed in the config file.
 -   Implemented Terminal service class, providing a generic terminal simulation.
 -   Added `User`, `UserManager` and `UserSessionManager` to enable the creation of user accounts and login on Nodes.
diff --git a/src/primaite/game/agent/interface.py b/src/primaite/game/agent/interface.py
index 14b97821..d5165a71 100644
--- a/src/primaite/game/agent/interface.py
+++ b/src/primaite/game/agent/interface.py
@@ -38,6 +38,9 @@ class AgentHistoryItem(BaseModel):
 
     reward_info: Dict[str, Any] = {}
 
+    observation: Optional[ObsType] = None
+    """The observation space data for this step."""
+
 
 class AgentStartSettings(BaseModel):
     """Configuration values for when an agent starts performing actions."""
@@ -169,12 +172,23 @@ class AbstractAgent(ABC):
         return request
 
     def process_action_response(
-        self, timestep: int, action: str, parameters: Dict[str, Any], request: RequestFormat, response: RequestResponse
+        self,
+        timestep: int,
+        action: str,
+        parameters: Dict[str, Any],
+        request: RequestFormat,
+        response: RequestResponse,
+        observation: ObsType,
     ) -> None:
         """Process the response from the most recent action."""
         self.history.append(
             AgentHistoryItem(
-                timestep=timestep, action=action, parameters=parameters, request=request, response=response
+                timestep=timestep,
+                action=action,
+                parameters=parameters,
+                request=request,
+                response=response,
+                observation=observation,
             )
         )
 
diff --git a/src/primaite/game/game.py b/src/primaite/game/game.py
index 045b2467..4f21120d 100644
--- a/src/primaite/game/game.py
+++ b/src/primaite/game/game.py
@@ -186,6 +186,7 @@ class PrimaiteGame:
                 parameters=parameters,
                 request=request,
                 response=response,
+                observation=obs,
             )
 
     def pre_timestep(self) -> None:
diff --git a/tests/integration_tests/game_layer/observations/test_obs_data_capture.py b/tests/integration_tests/game_layer/observations/test_obs_data_capture.py
new file mode 100644
index 00000000..e8bdea22
--- /dev/null
+++ b/tests/integration_tests/game_layer/observations/test_obs_data_capture.py
@@ -0,0 +1,28 @@
+# © Crown-owned copyright 2024, Defence Science and Technology Laboratory UK
+import json
+
+from primaite.session.environment import PrimaiteGymEnv
+from primaite.session.io import PrimaiteIO
+from tests import TEST_ASSETS_ROOT
+
+DATA_MANIPULATION_CONFIG = TEST_ASSETS_ROOT / "configs" / "data_manipulation.yaml"
+
+
+def test_obs_data_in_log_file():
+    """Create a log file of AgentHistoryItems and check observation data is
+    included. Assumes that data_manipulation.yaml has an agent labelled
+    'defender' with a non-null observation space.
+    The log file will be in:
+        primaite/VERSION/sessions/YYYY-MM-DD/HH-MM-SS/agent_actions
+    """
+    env = PrimaiteGymEnv(DATA_MANIPULATION_CONFIG)
+    env.reset()
+    for _ in range(10):
+        env.step(0)
+    env.reset()
+    io = PrimaiteIO()
+    path = io.generate_agent_actions_save_path(episode=1)
+    with open(path, "r") as f:
+        j = json.load(f)
+
+    assert type(j["0"]["defender"]["observation"]) == dict