A snorkel including a mouthpiece, a tube and a sealing member is disclosed. The tube extends from the mouthpiece and includes a first end proximate the mouthpiece, a second end and at least one internal passageway having a port proximate the second end. The sealing member is slidably coupled to the tube proximate the second end and is sealed about the tube. The sealing member moves between a closed position in which the member occludes the port and an open position in which the port is open. The sealing member has an interior in communication with the at least one internal passageway when the sealing member is in the closed position. In the exemplary embodiment, the sealing member is sealed to the tube via a flexible membrane. In an exemplary embodiment, the flexible membrane preferably includes a bellows. In the exemplary embodiment, the sealing member defines a first sealing surface which engages a second sealing surface proximate the port to seal the port along the first seal line that defines a first area. The sealing member is sealed against the tube along a second seal line that defines a second area, wherein the first area is greater than the second area.