A water bike has a frame supported on first and second spaced apart pontoons. Pedals are attached to cranks on a front sprocket rotatably supported on the frame. A chain or belt extends around the front sprocket and around a rear sprocket on a gearbox. An outdrive is supported on the gearbox and pivotal about a vertical axis relative to the gearbox. The combined outdrive and gearbox are pivotable about a horizontal axis relative to the frame. A propeller on the outdrive is mechanically linked to a first gear in the gearbox, with the first gear meshing with a second gear attached to the rear sprocket. A steering linkage connects a steering bar to the outdrive, for pivoting the outdrive to steer the water bike. An inflatable deck is attached to the first and second pontoons.