Alongside the new iPad Air 2 and iPad mini 3 Apple introduced the Apple SIM - a way to use just one SIM card and switch between carriers and their services.
However AT&T doesn't want to play along and will lock the SIM to only its services. Users have been seeing this disclaimer: "Once activation is complete this Apple SIM can only be used with AT&T. You will need a new Apple SIM if you change carriers in the future". Well that's not nice!
This leaves the Apple SIM compatible with Sprint, EE in the UK and T-Mobile in the US, which seems the only working right now in the US - Sprint may have some issues currently.
Interestingly if you buy a new cellular Apple iPad Air 2 or mini 3 from Apple or an authorized reseller you'll get an Apple SIM preinstalled but if you buy it from Sprint, for example, it will have a Sprint SIM.
It seems carriers aren't really on board with Apple's one for all plan just yet.
On Ipad with@apple sim here is what u see..no @Verizon ,@ATT trying to lock u, @sprint with error page! @TMobile wins pic.twitter.com/z0jDZ9sRt5
— John Legere (@JohnLegere) October 23, 2014Source | Via