Abstract: A water bicycle comprises a flotation board, a propulsion and seat unit including a mounting flange, a seat, foot pedals mounted for rotation driven by a person sitting on the seat, a propeller and a coupling connecting the pedals to the propeller, an opening in the board through which the propeller may pass and a surrounding edge surface able to receive the flange. A connector is provided for releasably connecting the flange to the edge surface. The bicycle includes a bore in the board with a bushing seat surrounding an upper end of the bore, a handlebar unit including a shaft and a bushing provided on the shaft above a lower end of the shaft, the bushing engaging the bushing seat and the shaft being supported and rotatable in the bore, and a rudder unit connected to the handlebar shaft.