Switching carriers on IPhone

Like WheelieNick said, "If your phone doesn't have a carrier lock on it, you should be able to."

Now about that"Carrier Lock" thing, if your phone is paid off and you've fulfilled any contract agreement with the carrier, there isn't any reason why they wouldn't release the lock on it.

Not all carrier's place the locks on devices they sell. I'm pretty sure that Verizon doesn't. The smaller carrier's probably still do though because they'll try to keep you from moving to one of the big guys.

If your iPhone is not carrier locked you should could change carriers