AT&T Locks Apple SIM to Their Network

Apple support document:

Using Apple SIM, you can choose from different cellular carriers and their various programs. The data plans vary by carrier. For instance, in the United States, you can choose a domestic plan from either Sprint or T-Mobile and also pick an alternate plan from the other carrier as needed. When you choose AT&T on iPad Air 2 and iPad mini 3, AT&T dedicates Apple SIM to their network only.

If your Apple SIM becomes dedicated to a specific network and you want to choose from other carrier programs, you can purchase a new Apple SIM from an Apple Retail store.

Sprint and T-Mobile leave the SIM alone.

Friday, 24 October 2014