Abstract: Two pivoting parts (8a, 8b) each mounted on one of the skis (1, 2) forming a pair are arranged so that each of them cooperates with two retaining parts (7a, 7b) each fixed on one of the skis. When each pivoting part (8a, 8b) is fixed via its free end to the retaining part (7a, 7b) of the same ski, the skis are separate (FIG. 1), whereas when these pivoting parts (8a, 8b) are rotated through 90.degree. and are fixed via their free end to the retaining part (7a, 7b) of the other ski, the two skis (1, 2) are locked in position relative to each other (FIG. 2). These parts allow the skier to change from conventional skiing to monoskiing and vice versa, by operating the pivoting parts and without having to remove his skis.