A submersible device for keeping track of a swimmer's session transpired times. It includes a case which is pivotally adjustable in relation to a base, and which contains both a watertight and a ballast compartment to decrease the buoyancy of the device when in use in water. The device may include a lap counter and a proximity sensor activated by the proximity of a swimmer wearing a proximity transmitter. A high contrast liquid crystal display is used to improve visibility.