Talk:United Kingdom/@comment-72.227.168.40-20130203195712/@comment-24682153-20150908082717

"Yes - US smartphones generally work in the UK."

I can't subscribe to this point of view. You are right, what the specific question of the user is concerned as he has an AT&T (= GSM) phone. But "generally work" is wrong. Don't forget that Verizon is still the biggest provider in the US using incompatible CDMA system.

Using a Verizon or Sprint phone, you need to be sure that it is unlocked and has a GSM SIM card slot (for 4G). These phones are often labled in the US as "world phones" by CDMA providers.

You still have some frequency incompatibilities, but 2G and 3G should be all right. 4G/LTE is still supported on very few phone models (like the iPhone 6) for both sides of the Atlantic at the same time.

Your remarks about unlocking are true for the US, but in other countries different regulations may apply.