The invention relates to a climbing locking system for vertical ladders, in particular of a wind turbine. The climbing locking system has at least one vertical ladder segment (20) having a longitudinal direction and at least one open end (20a, 20b) for accommodating a catching device, which can be moved back and forth in the longitudinal direction as a climbing protection system. The climbing locking system also has at least one climbing locking unit (10) at the at least one open end (20a, 20b) of the vertical ladder segment (20). The climbing locking unit (10) is pivotably fastened to the vertical ladder segment (20) and has a locking position for blocking motion of a catching device in a direction of the vertical ladder segment (20) and a passage position for letting motion of the catching device in the longitudinal direction of the vertical ladder segment (20) through in both directions.