So what is a phone unlocking? The majority of phone carriers put a lock on the phones they sell, which prevents their customers from using their phones with other network providers. Thus, if your phone is locked, it can only be used with a SIM card provided by a phone carrier your phone is originally locked to, and cannot be used with SIM cards of other phone carriers. For instance, if you try to use you locked phone with a third-party phone provider, on your phone\u2019s screen you will get a message stating that your SIM card has not been accepted.<\/p>\n