An unlocked cell phone hermes is not tied to any particular phone network. You can insert any SIM card into an unlocked phone and connect to the appropriate phone network operator. Your phone may be locked if it was not purchased from us. To check if your phone is locked, call your mobile service provider. The basic SIMsmart prepaid Europe Phone will not operate in the US. This phone only operates in regions using Dual Band frequencies (900/1800MHz).