IMS gateway systems and methods are disclosed for providing notification to an IMS subscriber. An IMS gateway system described herein includes a session manager and a notification database. The notification database stores a plurality of notification definitions for pre-session, mid-session, and/or post-session notifications. The session manager identifies a triggering event for a session of an IMS subscriber. A triggering event may be the initialization of a session, the account balance of the IMS subscriber running low, the termination of a session, or any other event as defined for the session manager. The session manager identifies at least one notification definition for the triggering event from the notification database, and provides notification (e.g., a pre-session greeting, a mid-session warning of a low balance, a mid-session request to recharge the subscriber's account, a post-session goodbye message, etc) to the IMS subscriber based on the notification definitions identified for the triggering event.