Disclosed is a 5G or pre-5G communication system to be provided to support a data transmission rate higher than that of a 4G communication system such as LTE. The present disclosure relates to a session management method through selection of a roaming operator and utilization of data usage rights of a local operator by a user in a 5G system. The user selects the local operator by switching the operator to a manual mode during roaming, accesses a data usage rights purchase agency through a limited service provided by the operator and then purchases the data usage rights of the local operator, and connects to a data network through authentication of a session by using authentication information included in the data usage rights.