Now I get to spend the next seven days determining whether I can actually open the box. I bought the phone through Apple, not through the carrier website, and I paid full price of $750 for it. It was listed on Apple's site as no contract, and definitely was not listed as unlocked. I am an AT&T customer, and my contract is not yet fulfilled and I plan to stay an AT&T customer. So if that makes this question very easy. Will i be able to take my AT&T Sim card out of my 5S and use it in the six?