An LED lighting fixture includes a metal core printed circuit board (MCPCB) having a rear side and a front side. At least one LED is mounted to the front side of the MCPCB. A transparent window is mounted and sealed to the front side of the MCPCB to enclose the LED. A portion of the MCPCB extends from the transparent window so that it can be in heat exchange contact with water when the window of the lighting fixture is submerged in water.