Methods and systems are provided to connect telephone calls, such as international phone calls, using both the data network and telephone network of a mobile communication device such as a cellular phone. These systems initially route a call to the destination phone number through a non-international temporary phone number, thereby saving the cost of an international phone call on the mobile phone's service plan. An application on the mobile phone uses the data network to automatically request and receive the substitute termination number, and automatically sets up a call on the telephone network to the substitute termination number, which routes the call to the desired international telephone number. These systems reduce the cost of an international call, permit mobile phone users without international calling plans to make international calls, and automatically connect to an international number through a temporary non-international number using dual networks.