A longitudinal adjuster (3), for a vehicle seat (1), includes a lower rail (9), an upper rail (11), moveable in relation to the lower rail (9) in a longitudinal direction (x), and a locking unit (13) for locking the upper rail (11) to the lower rail (9). The locking unit (13) includes two locking elements (VR), which, in order to lock the upper rail (11) and the lower rail (9), engage in the upper rail and the lower rail in a blocking manner in steps such that one of the locking elements (VR) pre-locks the upper rail (11) and the lower rail (9) with play in a pre-locking step and one of the locking elements (VR) locks the upper rail (11) and the lower rail (9) without play in a locking step. A vehicle seat (1) including such a longitudinal adjuster (3) is provided.