Find out if my iPhone is unlocked without purchasing. Your IMEI number for your iPhone and doing a free simlock check. Ee Iphone Unlock Instructions on this page. How To Unlock Iphone 4 Sprint Passcode on this page. Unlocked iPhone 4s with SIM. How To Unlock Sim Iphone 6 there. Whichever of these methods to check if your iPhone is unlocked or not works for you, the end result will be the same. If the iPhone is unlocked, you can continue to use it for however long you feel like but if it is locked, you might have to contact the carrier if you bought a used phone from a third party. How to check if iphone 4 is unlocked. I was leaving the US on a business trip and called AT&T on the off chance that they would unlock my on-contract iPhone 4S.