@Jason *******
sprint and Verizon work in CDMA, which is technologically different then GSM, used by T-Mobile, ATT, and all Thai carriers. However, iPhones have modems for both, so you can get a thai SIM card. Then you can have Google Maps, Facebook, etc, and use you line or Whatsapp. That being said, make sure your phone is unlocked. Especially many T-Mobile’s are locked. If you are staying in Thailand permanently, think carefully about giving up your USA cell phone account. I put mine on a Google Voice so I can get the texts from banks and credit cards, but recently they’ve started a thing where you have to have a real, American working cell phone, they verify with your carrier, not just have you enter the code.