"If you don't want a multiyear service contract, or if you prefer to use a local carrier when traveling abroad, the unlocked (no contract) iPhone is the best choice," Apple said in an online post.
Apple said an unlocked phone "does not come with a micro-SIM card for iPhone 4 and iPhone 4S, or a nano-SIM card for iPhone 5, so you'll need to get one from any supported GSM carrier worldwide."
Once a consumer buys a card, activating the phone is a matter of inserting the card into the iPhone, holding the On/Off button for a few seconds and following instructions, the company said.
Buying an iPhone 5 without a contract hints at how much carrier services are subsidizing the price of the device when a contract is included.
The iPhone 5 starts at $199 with a contract. An unlocked iPhone 5 starts at $649.