Built in 1853, the three-storey lighthouse and watchtower has an attached single-storey range to the east. They are built of rubble masonry with limestone dressings and slate roofs. The lighthouse and watchtower has battered walls and a hipped roof. The lower two storeys have exposed stonework including large limestone quoins at angles and above the second storey is a slightly advanced string course above which the elevations are rendered. The windows are six-pane casements, one to each storey of the south elevation, and a single upper storey window at the west end of the north elevation (facing out to sea). It is listed as good, well-preserved, mid nineteenth century lighthouse and watchtower which retains original character.

The small enclosing pier which created a harbour of refuge was built in 1816. The original lighthouse, which the present structure replaces, was built in 1817 and had a fixed bright light. The Watchhouse was used by the hobblers (rowing boats and their crews) which were responsible for towing vessels in and out of harbour.

The Harbourmaster's house which formerly stood adjacent to the Watch House to the east was demolished after being vanadlised.

Sources include:
Cadw listed buildings, NJR 14/07/2010
Amlwch Industrial Heritage Society, Porth Amlwch Heritage Trail leaflet

RCAHMW, August 2012.