Abstract: A cap includes a flexible body having a dome shape for conveniently conforming to a swimmer's head. The body includes an outer layer and an inner layer spaced from the outer layer such that a cavity is defined therebetween. The inner layer is provided with a plurality of conduits and a strap is integral with the outer layer and travels about a circumference of the cap. The present invention further includes a mechanism for effectively removing the stagnant air such that the inner layer can effectively maintain surface contact with the swimmer's hair and cooperate with the strap for preventing water from entering beneath the cap.