How To Unlock iPhone 5S Without Jailbreak: If you have bought an AT&T iPhone 5S without a contract over the past few days, chances are that you want to unlock it to use it on another carrier. Just restore the phone in iTunes and it will be unlocked.
After restoring the device in iTunes, the user is prompted with the usual unlocking message: “Congratulations, your iPhone has been unlocked.”
This message wasn’t enough for me though. I need more proof that I could use the iPhone on every carrier and abroad.
After receiving the notification my new iPhone was unlocked, I cut a micro-SIM card into the shape of a nano-SIM by using the AT&T SIM card that was already in the iPhone 5S as a guide. In a couple of seconds, the iPhone was able to pick up the T-Mobile network, and calls and EDGE data connectvity worked as expected. Some reports, including on AT&T forum, confirm this.
The iPhone 5S we tested was bought in an Apple retail store, but we couldn’t confirm this with another, pre-ordered iPhone 5S — even though the device was purchased at full price, it was tied to an existing AT&T account during the pre-order process. The carrier clearly states on its website that you have to be either a former customer or a customer without contract obligations to be eligible to go through the entire process, fax included. It could be problematic as well if you bought your iPhone 5S directly from AT&T.