# GroupSession A session for an in-progress activity that synchronizes content among participant devices. ``` final class GroupSession where ActivityType : GroupActivity ``` ## Overview A `GroupSession` object contains details about the user’s currently selected activity, its status, and its participants. When a participant engages in an activity, the system binds a session to that activity for you. You use the session object to synchronize your app’s activity-related content, including your app’s UI. You don’t create `GroupSession` objects directly. Instead, the system creates sessions and makes them available to your app asynchronously. Use the `AsyncSequence` type returned by the [`sessions()`](/documentation/GroupActivities/GroupActivity/sessions()) method of your activity to retrieve new sessions when they become available. Before the system can create a session object, your app must create a `GroupActivity` object and activate it. For information about how to configure group activities, see [`GroupActivity`](/documentation/GroupActivities/GroupActivity). ### Start and Stop the Session When you receive a new session object, it’s initially in the [`GroupSession.State.waiting`](/documentation/GroupActivities/GroupSession/State-swift.enum/waiting) state. As soon as your app is ready to begin the associated activity, call the session’s [`join()`](/documentation/GroupActivities/GroupSession/join()) method. Joining a session validates the connection and starts the synchronization process between the current device and other participants’ devices. If your app successfully joins the session, the session transitions to the [`GroupSession.State.joined`](/documentation/GroupActivities/GroupSession/State-swift.enum/joined) state. When the user quits your app, or navigates away from the shared activity, call the session’s [`leave()`](/documentation/GroupActivities/GroupSession/leave()) method. Leaving a session gracefully transitions it to the [`GroupSession.State.invalidated(reason:)`](/documentation/GroupActivities/GroupSession/State-swift.enum/invalidated(reason:)) state, and informs the system that the user isn’t currently engaged in the activity. ## Topics ### Getting the current session [`GroupSession.Sessions`](/documentation/GroupActivities/GroupSession/Sessions) An asynchronous sequence of sessions you use to manage a specific activity. ### Joining and leaving the session [`join()`](/documentation/GroupActivities/GroupSession/join()) Starts the shared activity on the current device. [`leave()`](/documentation/GroupActivities/GroupSession/leave()) Leaves the current activity and stops receiving synchronized data. [`end()`](/documentation/GroupActivities/GroupSession/end()) Ends the activity for the entire group and stops the transfer of synchronized data. ### Accessing the shared activity [`activity`](/documentation/GroupActivities/GroupSession/activity) The current activity associated with the session. ### Getting the session details [`state`](/documentation/GroupActivities/GroupSession/state-swift.property) The current state of the session. [`GroupSession.State`](/documentation/GroupActivities/GroupSession/State-swift.enum) The possible states of a session. [`id`](/documentation/GroupActivities/GroupSession/id) The unique identifier of the current session. ### Getting the participants [`localParticipant`](/documentation/GroupActivities/GroupSession/localParticipant) The participant on the current device. [`activeParticipants`](/documentation/GroupActivities/GroupSession/activeParticipants) The set of participants currently engaged in the activity. ### Getting the scene-association identifier [`sceneSessionIdentifier`](/documentation/GroupActivities/GroupSession/sceneSessionIdentifier) The persistent identifier of the session’s associated scene. ### Getting the participant’s attention [`requestForegroundPresentation()`](/documentation/GroupActivities/GroupSession/requestForegroundPresentation()) Tells the system that your app needs to be in the foreground to continue an activity. ### Notifying participants of playback changes [`showNotice(_:)`](/documentation/GroupActivities/GroupSession/showNotice(_:)) Posts an event to the system, which displays the information in the system UI. [`GroupSessionEvent`](/documentation/GroupActivities/GroupSessionEvent) A session-related event that appears in the system UI. ### Publishing changes --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)