Switching carriers or using a different SIM card on your iPhone doesn’t have to be complicated. If your device is SIM-locked, ...

How to Use Your Unlock Code Once you have acquired your SIM unlock code, follow these steps: Turn off your phone and insert the new SIM card.

If you're a new T-Mobile customer or you recently purchased a new phone, you may have a new SIM card you'll need to activate. Here's how to set it up.

If you've just got your hands on a shiny new Sim card, congratulations. Switching your Sim (the chip that dictates your allowance) can unlock huge savings. Now comes the crucial step of activating it ...