A method, system, and terminal for handling or processing roaming errors between networks that can support broadcast services is provided. When a roaming service between networks is requested, if a user authentication request is unsuccessful due to non-matching identification information between the networks, a corresponding error message is delivered to the subscriber terminal and network information that has been recently updated using various methods is provided such that repetitive requests and responses for authentication can be avoided when the subscriber requests a roaming service, and thus a roaming service between networks can be quickly provided without delays.