A self-powered illumination device includes an illumination source protruding from its lower surface for projecting light into a body of water to provide light that is emitted preferentially outwardly to illuminate the sides of a pool. Light emitted with an upward angle of inclination strikes the underside surface of the water-air interface surrounding the device and is reflected outwardly and laterally away the from the light source after striking such underside surface. Preferably, the illumination source has a length that extends downwardly that is commensurate or greater than its width and may be in the form of a fluorescent tube. The illumination device is fully self righting when inverted on the surface of a body of water.