A:AnswerThe Sim card varies for the type of phone you use but your network which is the GSM depend on your country frequency that determines a lot. I don’t believe AT&T is available international but they do have affiliates.
A:Answerhttps://www.att.com/buy/wireless/prepaid/plandetails
Always a catch. If you use more than 22GB they have the right to throttle you back. If you tether/hot spot you get 10GB and that is it. Go to the link above and check out the details.
A:AnswerYes, unfortunately if you do not use the number for beyond 45 days it does expire. It may stay active if you keep adding funds on your SIM or recharge funds assuming its Prepaid each month while you're away, however I still think it does get deactivated in case the SIM is unused for calls/texts for beyond 45 days. Good luck though!