Subscriber identity modules can be bound to devices and utilized for authentication. An initial or additional subscriber identity module can be bound to a user device, for instance after successful user authentication by way of an alternate mechanism. A subscriber identity module of a device can be identified, and carrier data associated with the subscriber identity module can be requested and received. A determination can be made regarding whether the subscriber identity module is linked to the device, for instance by an original linkage. A user profile can be automatically updated with the carrier data to bind the user to the user device based on the subscriber identity module when the subscriber identity module is verified to be linked to the user device. Subsequently, the subscriber identity module can be utilized as a basis for authentication.