Methods, systems, and computer readable media for unifying fixed and mobile devices via third party call control (3PCC) are disclosed. The method is performed at a dedicated application server (AS) that supports a third-party call control (3PCC) interface. According to one method, a call addressed to a unified subscriber identifier associated with a terminating subscriber is detected, where the terminating subscriber is associated with two or more terminating endpoints. The call is offered to each of the terminating endpoints by initiating signaling to each of the terminating endpoints using the 3PCC interface. One of the terminating endpoints used to answer the call is detected and the call is redirected to the terminating endpoint used to answer the call. Signaling messages are sent to all of the terminating endpoints other than the terminating endpoint used to answer the call for instructing the terminating endpoints to release resources associated with the offered call.