Systems and methods for avoiding roaming or communications charges when a mobile communications device such as a cellular telephone receives an incoming telephone call use a non-native communications provider, such as a VOIP service provider to redirect the call. A subscriber's mobile communications device establishes a data connection to the VOIP service provider through a data network, and call forwarding instructions are issued to the subscriber's telephony service provider to cause calls directed to the subscriber's mobile communications device to be redirected to a forwarding telephone number associated with the VOIP service provider. When a call is placed to the subscriber's normal telephone number, the call is forwarded to the VOIP service provider. The VOIP service provider establishes a VOIP communications channel with the subscriber's mobile communications device via a data network, and the incoming call is connected to the subscriber's mobile communications device via the VOIP communications channel.