Multi-carrier Apple SIM 'dedicated' to AT&T's network upon activation, not carried by Sprint Stores

With its latest cellular-connected iPad models, Apple introduced the "Apple SIM," a micro-SIM card compatible with multiple wireless providers around the world. At launch, Apple announced AT&T, Sprint, T-Mobile and the UK's EE as participating carriers, but it appears some telcos are pushing back against the initiative.

As noted by iMore, a support document posted to Apple's website on Friday points out a few limitations to its Apple SIM hardware, as imposed by cellular providers.

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.

By dedicating Apple SIM to its network, AT&T nullifies much of the utility offered by Apple's system. If an AT&T iPad owner intends to switch between carriers using short-term subscriptions, they will need to get a new Apple SIM for outside networks. This is basically how the system worked prior to Apple SIM.

It should be noted that AT&T is not locking in iPad hardware, meaning users are free to change carriers so long as they acquire a new Apple SIM from that provider or Apple.

The document also notes that Sprint Stores will not include Apple SIM with new iPad purchases, instead opting for "legacy Sprint SIM cards" that assumedly do not support multiple carriers.

If you purchase your iPad Air 2 or iPad mini 3 from a carrier retail location, your Apple SIM will only be compatible with that carrier's program. If you purchase your iPad Air or iPad mini 3 from an Apple Retail, Apple On-line store, or a reseller within countries where Apple SIM is supported, you'll have all participating carriers to choose from.

Apple Online Store: All supported carriers in that country

Apple Retail Store: All supported carriers in that country

Reseller: All supported carriers in that country

Participating carrier store: Only the carrier from that carrier store

Note: Sprint Stores will only carry iPads with legacy Sprint SIM cards (not Apple SIM cards).

The issue is more confusing for T-Mobile. A supposedly leaked internal document suggested the company would also be locking the Apple SIM onto its network, at least those units included in iPads sold through the telco's retail chain. However, a series of tweets from CEO John Legere suggests T-Mobile is not locking in Apple SIMs and will provide full multi-carrier compatibility as Apple intended.

For now, those in the market for a new iPad may best be served by making the purchase through Apple's online or brick-and-mortar stores, not official carrier outlets. In the case of AT&T, however, activating the iPad will tie the included Apple SIM to the carrier's network. It is unclear if Sprint and T-Mobile do the same.