A tail light to be installed onto the end of a boat motor propeller, to increase visibility of the propeller when the boat is being hauled on a trailer. The tail light includes a light fixture secured to a mounting plate. The mounting plate is configured to fit onto the propeller hub. A strap releasably secures the tail light in position on the hub. The tail light is wired to wiring of the trailer to illuminate the location of the end of the propeller when the boat is secured on the trailer.