A navigation light system for a watercraft including multiple lights of a common color and that are spatially separated on the watercraft to collectively operate as a navigation running light that has a specified horizontal beam sector of less than 360 degrees. Each light is separately masked to emit light outwardly from the watercraft within a partial arc horizontal beam sector which is less than the specified horizontal beam sector. The navigation light system may include first and second running lights of first and second colors, respectively, where each running light includes multiple commonly-colored lights that are separately masked within a corresponding one of mutually exclusive partial arc horizontal beam sectors within the specified horizontal beam sector.