Abstract: A communication system provides for an Internet Protocol Multimedia Subsystem (IMS)-based three way call. A mobile station (MS) that receives an invitation to participate in a call determines to switch the call to a three way call. The MS conveys a request to an IMS network to switch the call to a conference call. An IMS network server receives the request, determines a unique identifier for the conference call, and provides the conference call identifier to the MS via one or more of a Session Initiation Protocol Refer message, Message message, and Notify message. In response to receiving the conference call identifier, the MS dials into the conference call and requests that the call originator also dial in. The IMS network server then requests that the call originator dial in, and the call originator does so in response to the request.