A method and apparatus for supporting an early data transmission (EDT) in a radio resource control (RRC) inactive state is provided. The current gNB receives a resume request message including uplink (UL) data from the wireless device, and transmits a logical channel identifier (LCID) for the UL data to the last serving gNB. The last serving gNB transmits UL forwarding user plane (UP) transport network layer (TNL) information to the current gNB based on mapping between the LCID for the UL data and data radio bearer (DRB) ID or protocol data unit (PDU) session ID in a UE context stored in the last serving gNB. The current gNB forwards the UL data to a core network via the last serving gNB based on the UL forwarding UP TNL information.