Systems and methods for terminating telephony communications to a mobile telephony device via a data network make use of a forwarding termination service. The forwarding termination service causes a native mobile telephony service provider that provides service to the mobile telephony device to forward incoming telephony communications directed the native telephone number of the mobile telephony device to a forwarding access number. The forwarding termination service receives telephony communications directed to the forwarding access number, and then terminates the telephony communications to the mobile telephony device via any one of multiple different methods. The mobile telephony service provider can be instructed to implement and cancel call forwarding instructions by a forwarding agent that is separate from the forwarding termination service.