answer:Phones in the rest of the world work off SIM cards. She probably will not be able to use her current phone; we have Sprint, and none of our phones worked in France or China. We did have a plan with Mobal when my daughter was in China, that allowed us to charge phone calls to a credit card. The down side of this was, when she traveled to Hong Kong, the SIM for China didn’t work, so she had to purchase one for Hong Kong, and lost the China one. Not realizing it could be a problem, she never mentioned losing it, until someone who found it wracked up $1200 in calls to Canada on it, which we had to pay for. She may do better waiting until she gets to Japan and purchasing a phone there.