Bad news buyers looking to purchase a new Apple iPad Air 2 or iPad mini 3 on AT&T's network -- your SIM will be locked.

"When you choose AT&T on iPad Air 2 and iPad mini 3, AT&T dedicates Apple SIM to their network only," reads an Apple support document.

 Cellular models of Apple's new iPads come with their very own Apple SIM installed. Quite simply put, Apple SIM moves away from the archaic little pieces of plastic we've all come to know and more into the realm of a reprogrammable chip.

"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" explains Apple.

Apple SIM currently works with AT&T, Sprint, and T-Mobile networks in the United States and with EE in the United Kingdom. Apple plans on expanding the portfolio to include carriers from around the world. If all goes well, frequent travelers will be able to fly all over with their iPads and never lose connection.

Which is what makes the AT&T lockdown so frustrating. Luckily, Apple does state: "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."

Bear in mind the iPad itself remains unlocked even if the Apple SIM inside of it only works with AT&T. The only thing customers have to do is switch out the SIMs, but it's still an inconvenience.

"With us you can change carriers with this iPad any time you want," AT&T spokesperson Mark Siegel told Re/code. "It is an unlocked device. ... All [you] have to do is switch out the SIM in the device so it works on another carrier."

It's unclear what AT&T's motives are behind the rule and there doesn't seem to be any explanation in sight.

"It's just simply the way we've chosen to do it," Siegel bluntly said.

The cellular iPad Air 2 model with its 9.7-display starts at $629 while the cellular iPad mini 3 and its 7.9-inch screen starts at $529. Both iPads feature Apple's high-resolution Retina display and are the thinnest to date.

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