A method for sending an end marker, a device, and a system, where the method includes receiving, by a source access node (AN) through a source path between the source AN and a core-network user-plane device, a first end marker sent by the core-network user-plane device. The method further includes generating, by the source AN, N second end marker(s) based on the first end marker, where N is a number of source data radio bearers (DRBs) corresponding to the source path, and sending, by the source AN, the N second end marker(s) to a target AN through a forwarding path corresponding to the source path.