Poolbeg Lighthouse, Lighthouse at Dublin Bay, Ireland

Poolbeg Lighthouse is a round, tapered tower painted bright red, standing on a platform of dark, uneven rocks at the end of the Great South Wall. It rises about 20 metres to a railed balcony and a small lantern room with diamond-pane glazing under a pointed red dome. A short white-walled entry section with a white door sits at its base, and small windows and round portholes run up the shaft.

The lighthouse was built in 1767 to guide ships into the River Liffey and Dublin Port. It was upgraded from candlepower to oil illumination in 1786, making it more visible to passing vessels.

The red colour is a navigational code: vessels entering the port keep red markers to port and green to starboard, so Poolbeg contrasts with the green North Bull and North Bank lighthouses across the channel. The tower is managed by Dublin Port Company, not the Commissioners of Irish Lights.

The lighthouse is reached by walking along the South Bull Wall, which can be partially submerged during high tide. Wear sturdy footwear and exercise caution in poor visibility or rough weather conditions.

The Ordnance Survey of Ireland took the low-water mark of the spring tide on 8 April 1837 at Poolbeg Lighthouse as the standard height for all its maps, a practice kept until 1958. The tower is managed by Dublin Port Company, not the Commissioners of Irish Lights.