While the cellular versions of iPads have always been unlocked, customers would have to pick their cellular providers at time of purchase to ensure that SIM card would be pre-installed. With the new Apple SIM, one SIM card will work with multiple US and UK carriers. Customers can now switch back and forth between cellular providers, depending on which provider suites them best at that moment.
The new Apple SIM is preinstalled on iPad Air 2 with Wi-Fi + Cellular models. The Apple SIM gives you the flexibility to choose from a variety of short-term plans from select carriers in the U.S. and UK right on your iPad. So whenever you need it, you can choose the plan that works best for you — with no long-term commitments. And when you travel, you may also be able to choose a data plan from a local carrier for the duration of your trip.
US Carriers AT&T, Sprint and T-Mobile are all supporting the Apple SIM. Verizon is not participating in the Apple SIM Program, so those customers must visit a Verizon store if they wish to use a cellular iPad with Verizon.