A port light assembly for watercraft having an exterior frame comprising a finish ring and a spigot defining a port light opening. The spigot is inserted in a hole in a vessel hull from the exterior of the vessel. The spigot is configured to provide drains to keep water from pooling near the port light. The exterior frame is connected to an interior frame that is placed around the spigot from the inside of the vessel. An innermost frame, retaining a glass lens, is hingedly connected to the interior frame. The assembly includes a screen installable from inside the hull. The frames are constructed from plastic and reinforced by strips of non-corrosive metal. The assembly is adjustable for hull thickness. The assembly is installed without the use of caulk or adhesives, it provides a watertight seal between the exterior and interior of the vessel.