This is a CDMA phone. It works on the Sprint network. It might work on Verizon provided you talked Verizon into allowing it on their network. You can roam in Japan with it. We learned this the hard way via high roaming bill due to a trip to Japan. I don't know if you could use it on a network there or not. It does not use or have a place for a sim card. It is not a GPRS phone. It will not work in Europe for example.