The Poolbeg Lighthouse is an active lighthouse located at the mouth of the River Liffey.
Walking to Poolbeg Lighthouse from Sandymount (which can be reached by bus) takes about 11 km. A shorter walk of 2 km can be taken from Pigeon House Road.
The first building was constructed in 1767 and operated on candles until 1786, when it was converted to oil. In 1820, it was rebuilt in its present form.
Currently, the red color of the lighthouse indicates 'port' in Dublin Bay, while the green color of the North Bull lighthouse indicates 'starboard'.
On the seawall leading to the lighthouse, there is a spot where you can dive into the sea to swim: the Half Moon Swimming & Waterpolo Club, was founded in 1898.