A handover method, performed by a source base station in a wireless communication system, includes: receiving an indicator indicating a start of packet duplication transmission of a user plane function (UPF); and transmitting at least one redundant packet to a target base station, based on the indicator indicating the start of the packet duplication transmission of the UPF, wherein the packet duplication transmission includes transmitting, to the target base station, a packet that is identical to a packet transmitted by the UPF to the source base station, wherein the redundant packet includes a packet that was received from the UPF before the start of the packet duplication transmission but is not transmitted to a User Equipment (UE) and stored.