The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method performed by an access and mobility management function (AMF) in a communication system includes receiving, from a user equipment (UE), a registration request message, receiving, from a unified data management (UDM), subscription information for session management function (SMF) selection including an identifier (ID) of a target public land mobile network (PLMN) for traffic routing, and selecting an SMF for traffic routing in the target PLMN based on the ID of the target PLMN included in the subscription information.