Abstract: A device useful for exercising in a swimming pool or other body of water which allows the person to be supported in a substantially seated upright position in the body of water such that the neck, head and upper shoulders of the person remain out of the water, allowing the person to exercise the legs, arms and torso while neutrally buoyant. The device is constructed of a buoyant body that is contoured to be stable and recessed laterally to be comfortably straddled by a person exercising, and includes a smaller forward portion and a larger (in volume) rear portion upon which the person is seated while in the water. The particular shape of the device is such that the center of buoyancy of the body is positioned to substantially be disposed forward of the vertical spine (near the center of gravity) of the user for balance and stability in the water. The user, may thus sit upon the body and freely move his legs and arms for exercise in a seated, upright position.