For years, customers have been dealing with carriers locking cell phones but why do they do it?
Locking your newly purchased smartphone is a great way for your carrier to make sure they keep you as a customer. The term "locked" refers to a devices being "SIM locked". What this means is that the phone locked to that specific carrier and all the settings are optimized for that carrier.
If you put another carriers SIM into the phone then it will not work - until you get the phone unlocked by the carrier who supplied it.
These reason the phone will typically come locked, is so the customer does not leave their commitment or terminate their service early. Some carriers require the phone be active with their service for a minimum of 1 year prior to the phone being eligible for unlocking.
Once the phone is unlocked, you'll have the option to consider other carriers that are compatible with your newly unlocked device.