Adjustable water ski bindings are utilized to attach water skis to the feet of skiers and consist of a foot piece which is stationary on the water ski and a heel piece which is adjustable lengthwise of the water ski. In order to attach the water ski to the foot, the toe is first inserted into the front vamp or foot piece and then the heel piece is pressed against the heel until a tight fit on the foot is accomplished. The heel piece can be attached to a mounting plate which is slidable in guides attached to the ski on opposite sides of the plate. The mounting plate can carry two latch members having teeth which cooperate with ratchet teeth on the guides and when the teeth are engaged, the heel piece will be locked against rearward movement which would loosen the heel piece. Quick loosening of the heel piece can be accomplished by disengagement of the teeth by movement of the latch members so that the skier is able to quickly remove the ski from his foot in the event of a fall into the water. Present locking mechanisms for the heel piece utilize pawl or latch members and springs which are unnecessarily complicated since either pivots or guide slots are required in the mounting plate for the latch members and separate springs are required for these members. The U.S. Pat. to W. J. Meucci No. 3,137,014 is an example of guide slots cut in the mounting plate for latch or pawl members. The use of pivots connected to the mounting plate for latch or pawl members is illustrated by U.S. Pat. Nos. to H. A. Moline 2,970,325; B Roudebush 3,127,623; and W. W. Bennett 3,102,279. Also, the patent to R. I. Rumig, 2,866,210 requires a separate spring attached to the mounting plate for the latch member. These prior locking mechanisms for ski bindings are unnecessarily expensive and are, under some circumstances, difficult to operate during attachment and removal of the ski from the foot.