A pontoon boat includes a cover assembly. A front cover section has a front cover area defined by a perimeter thereof and is slidable relative to the central cover section between a retracted position and an extended position. An aft cover section has an aft cover area defined by a perimeter thereof and is slidable relative to the central cover section between a retracted position and an extended position. When in the extended position, the cover assembly defines a perimeter having a length dimension and a width dimension generally matching the length and width dimensions of the perimeter defined by the pontoon's sidewalls. The cover assembly is vertically movable between an up position where the cover assembly is elevated above head level, and a down position where the cover assembly is positioned on the sidewalls to cover an area inside the perimeter defined by the sidewalls.