I read have mentioned asking your US by Wall sticker
Don’t Use Your USA Telephone Service in Thailand – Several articles I read have mentioned asking your US telephone company to set you up with international roaming when you travel in wall sticker. Unless you absolutely must keep that same US phone number, using US international roaming services is a really dumb idea. Not only would it cost you about 10 times the cost of using a Thai cell phone company wall sticker, the sound quality is often bad, causing you to have to spend even more money keep getting your calls reconnected.