How the Apple Sim card works in the US - 1)The Apple Sim card will allow you to activate the iPad with Sprint, ATT, and T-Mobile. With some basic clicks you should be ready to go. Verizon chose not to participate. If you want to switch carriers later on, this device is completely unlocked. All you have to do is purchase a SIM from the carrier you want to switch to. How the Apple Sim works outside the US- 1) Every country has different participating providers that connect via the Apple Sim Card. You can purchase a SIM card from any Cellular network and swap out the Apple Sim card for card from a local carrier.