Abstract: A supportive frame of crossed, intersecting and interconnected frame members is provided with the frame being horizontally disposed and of a plane shape and area conforming to the plane shape and area of an associated swimming pool. The supportive frame includes cover panel structure supported therefrom and is suspended over the associated swimming pool by suspension cables and the cover may be lowered downwardly over the pool by the cables. The cover includes peripheral notches formed therein for receiving a diving board and pool steps and the cables supporting the cover are spaced along the latter in one direction thereof whereby guide pulleys anchored above the cover may have the cables passed thereover and elevated winding drums spaced along one marginal edge of the cover in the aforementioned direction may have the cables wound thereon for the purpose of raising and lowering the cover relative to the pool upon selective rotation of the winding drums.