Can I use iPhone 5 no contract version with T mobile contract?

The unlocked iPhone 5 is not yet available.

Once it is, you're welcome to use it with any GSM carrier you want.

Keep in mind that T-Mobile in the U.S. is not a supported carrier and their network is largely incompatible with the iPhone.

Well... take a look at the web page where you see that... now try to order one... what happens?

AT&T will sell you a nice new iPhone 5 at full retail price and with no contract obligations - prices are right there on the AT&T web page.

Those phones, however, are still carrier locked to AT&T, and it is not at all clear if they will unlock them without completing some period of service with AT&T first.

Then go there and buy one if you want. Officially, Apple is not selling an unlocked version of the iPhone 5 in the U.S. at this time.

yh83 wrote:

This is a good explanation. Rumor said this kind of iphone can be used on other carrier.

Isn't that a great thing about the internet? Search hard enough, and you can always find a rumor that says you can do what you wanted to do in the first place.

Don't be fooled, a "no contract" AT&T phone is NOT a carrier unlocked phone!

Note that you must BE a current AT&T subscriber or a previous one. So unless you were an AT&T customer already, you will have to sign up for service before they will unlock it (don't know if you could use a GO SIM to do that or not)

."Apple won't unlock any iphone but ATT will do"

Apple has never authorized unlocks of carrier unlocked iPhones - never worked that way. You always have to requrest the unlock via the carrier, who then works with Apple to provision the unlock request in the iTunes servers so it gets processed when you restore the phone in iTunes. Carriers authorize unlocks, and Apple processes them through iTunes.

Oh, and also note that you will not get LTE data speeds with T-Mobile using an iPhone 5