Hello vanessal In short, no. In order to sign up for post-paid service you must have a US billing address. You must also be on AT&T's domestic network most of the time. International Roaming Rates depend on your geographical location and coverage depends on the local network AT&T has a roaming agreement with. For prepaid service, you are only able to roam in Mexico and Canada, and you must have sufficient balance to cover the use prior to entering the countries.