Depending on where you buy it, your Android phone may be unlocked and can support SIM cards from any carrier, or it could be carrier-locked and require specific SIM cards. While it’s not always ...

If the contract period is over, the phone may be unlocked by entering a code from the carrier. Apple's iPhone ... a recipe for marketing failure. See SIM card and iPhone jailbreaking.

After that period, the lock is removed and you are able to insert a new SIM card and change your wireless carrier. How to unlock a Verizon phone you purchased from a retailer If you purchased the ...