Phones listed with a specific carrier are guaranteed to work only on that specific carrier. These are called “locked” phones, as they have software locks that prevent them from being used on any carrier except the one that originally sold it.
It’s important to remember that a carrier lock is a matter of compatibility— none of these phones come with a contract or specific plan attached.
We also carry a wide range of unlocked phones. An unlocked phone is one that can be used with almost any carrier.