Best thing to do is to contact your provider or locate a cheap online unlock site. They'll usually unlock your phone for a small fee.

If you get an S3 you'll probably want to get the T-mobile variant, SGH-T999 (will be cheaper than the global one and has the 1700/2100 bands). The LTE Bands that AT&T use are different from just about everyone else in the world, so you wouldn't be able to use LTE anywhere other than the states. However, the T-mobile version doesn't have LTE enabled at all, just HSDPA+.

If you really want to get complicated you could root it and load a custom ROM with all antennas enabled.

Hi everyone, I need someone to help me understand this better. I'm an entrepreneur and travel a lot from within North America and also to Asia. I currently live in Canada and the carriers that we have are Rogers, Telus and Bell (which has the LTE and GSM bandwidth, similar to AT&T and Verizon in the States) and we also have Wind Mobile, Mobilicity (which uses the AWS 1700/2100 bandwidth, similar to T-Mobile in the states). I am currently using Wind Mobile (as it is much more economical), but their bandwidth is the AWS 1700/2100 and when I go to Asia they only have the GSM / LTE bandwidths there. So everytime I travel I find myself carrying two phones which is a pain.

So here's my question. If I buy the S3 or the Note 2 is there a version that I can buy so that I can unlock it and work with all the carriers with different bandwidths out there? I like to use it at home with WindMobile, but also be able to use it on AT&T network when I'm in the States or other GSM/LTE network when I'm in Asia.

Sorry if this question may sound kinda dumb to most of you out there, but I'm not that techie and would really appreciate if you guys can help me clear this question. Thanks.

Last question, how about other phones such as HTC One S, Xperia T or even the Nokia Lumia can it be unlocked to work with all the carriers (AWS / GSM / LTE network carriers) as well?

Thank you very much everyone!