Apple begins selling unlocked, SIM-free iPhone 6 and 6 Plus models

In the U.S., customers have been able to buy an unlocked iPhone 6 and iPhone 6 Plus from day one, but it would ship with a T-Mobile SIM card inserted. Starting Tuesday, the Apple Store began offering a SIM-free option starting at the same $649 price for the entry-level 16-gigabyte iPhone 6.

The new unlocked iPhone 6 model is identified as A1586, while the iPhone 6 Plus is model A1524. They are compatible with carriers around the world, and for U.S. customers can be activated on AT&T, T-Mobile, Verizon or Sprint.

The new phones are actually different than the T-Mobile unlocked handsets, which are identified as model A1549 for the iPhone 6 and A1522 for the iPhone 6 Plus.

The new SIM-free iPhone 6 and iPhone 6 Plus option may be less confusing for consumers looking to buy an unlocked handset for use with GSM carriers abroad, but who might be thrown off by the inclusion of a T-Mobile SIM. Further obscuring matters, while iPhone 6 units sold from the Apple Store ship unlocked, handsets sold through the carrier T-Mobile are locked to its network.

It's also a new option for contract-free Verizon and Sprint customers looking to upgrade and pay full price for an unlocked handset.

With SIM-free iPhone 6 models now available through Apple's online store, it's likely that units will also begin to show up in the company's retail stores this week. Contract-free iPhone 6 pricing increases to $749 for 64 gigabytes, and $849 for 128 gigabytes, while the iPhone 6 Plus starts at $749 for 16 gigabytes and has $100 price increases for each corresponding capacity increase.