said by wingdo :Understood. But 'supporting' means they can accept a SIM card. You just don't get one with your contract; meaning you typically have to buy a SIM card in the country your visiting; or from AT&T or T-mobile here. Exactly my point. There will be only one provider here.
I cannot speak for Sprint, but Verizon has a number of "world phones" which are CDMA / LTE but support GSM outside the US. AT&T would not be the only way to use your cell phone out of the country.