I just ordered an iPhone 6s through the Apple Store and chose T Mobile as my carrier due to the fact that they are unlocked if paid in full. I've seen other people use AT&T SIM cards with the T Mobile phone but I'm scared that the Straight Talk nano sim will not work with it. I currently have an iPhone 4 with no sim and have been told I can transfer my number once I get the Straight Talk nano sim and put it in the iPhone 6s. I am really going to be disappointed if I can't use Straight Talk with my new iPhone 6s (which won't be delivered for 3 weeks) wont activate with the Straight Talk SIM card. Has anyone successfully used Straight Talk with an IPhone 6s? I'm fuzzy on the ins and outs of how it all works so please excuse me if some of my questions sound silly. Any help would be greatly appreciated.