An apparatus is described for use in stabilizing a watercraft such as a kayak or canoe during boarding and exiting the watercraft. The apparatus includes a pair of spaced pontoons having above-water surface areas, below-water surface areas, inner sides, and lengths equal to from about 0.25 to about 1.0 times the length of the watercraft. The pontoons are joined in a spaced, parallel relationship by horizontal supports having lengths approximately equal to the width of the watercraft. The supports are transverse to the longitudinal axes of the pontoons and having opposed outer ends attached to the pontoons, e.g., to the below-water areas of the pontoons, whereby the supports are below water level when the apparatus is resting on the surface of the water. The apparatus preferably also includes rollers or support saddles mounted on the supports to facilitate movement of the watercraft onto and off of the apparatus.