An improved method and system for removing operating restrictions associated with a predetermined subscriber identity module (SIM) from a wireless device. A user is allowed to securely log onto a Web site that contains support information on subscription plans, billing, termination, penalties, and device-to-SIM unlocking. After satisfying any outstanding contract terms and payment of termination or device unlock fees, the user initiates a device-to-SIM unlock procedure. A client application on the wireless device securely transfers subscription, system, and SIM information to a device-to-SIM unlock system which uses the information to generate appropriate unlock codes. The unlock codes are then securely transferred to the client application, which processes them to remove operating restrictions associated with the predetermined SIM from the device and allow it to thereafter implement a plurality of SIMs.