A fiber optic light system for illumination use in a swimming pool or spa environment or the like. The light system includes a light source unit positioned at a suitable dry site for delivering a relatively intense light signal to the input end of one or more optical fibers, wherein this light source unit may include a color wheel for controllably varying the color of said light signal. A support manifold includes a retainer disk for substantially aligning the input ends of the optical fibers with the light signal for optimizing light input thereto. The output ends of the optical fibers are captured within a sealed lens assembly mounted at a submerged or underwater location such as within a pool or spa wall. This lens assembly includes multiple lens segments for distributing the light in a controlled manner within the swimming pool or spa.