A method and system for extending Camp-On Capabilities to invitees to an ongoing conference call. In one embodiment, a persistent invitation is extended to a first network station client to join a conference call in response to a determination that the first network station client is unavailable to accept a non-persistent invitation to join the conference call, and the first network station client is added to the conference call when the first network station client accepts the persistent invitation to join the conference call. In another embodiment, a persistent invitation to join an ongoing conference call is presented to an initially unavailable network station client, and the persistent invitation to join the ongoing conference call is accepted in response to user input to a network station client including but not limited to the initially unavailable network station client and another network station client where the user has been authenticated.