You'll need your iPhone's IMEI number if you want to unlock it and use it on a different cellular provider.

You can check to see if your iPhone is unlocked from a carrier using any of a few different methods.

Knowing your IMEI and ICCID iPhone numbers is important, as these numbers enable you to identify your phone in case of theft. Your IMEI number serves as a unique identification number for your iPhone, ...

how do i find the imei on this thing? it doesn't say in the sim card holder area, or the back of the device.. and it doesn't turn on? Can you punch the serial number in on Apple’s website and see if ...