A buoyant, flexible, resilient aquatic mat for use on water surfaces adapted to support one or more persons. The mat comprises an elongated slab and a headrest formed of the same material. The material of the mat comprises a unicellular, non-water absorbent, plastic foam. The material comprising the mat may have a tough plastic coating over the entire surface or by use of a suitable plastic foam material the material comprising the mat may be used without a coating. A series of parallel grooves with rounded inner surfaces extends into the mat from its lower surface. The grooves formed with heated rounded bars to provide density increased skin surfaces in areas of the grooves.