51°23.3' North
9°36.1' West
Fl W 5s. White every 5 second.
Range 27 NM.
Height of Tower
Height above MHWS 49 M

The light on the Fastnet rock was first lit on 1st January 1854 it replaced a shore light on Cape Clear island erected in 1818, the Fastnet is located on a rocky island 6.5km south-west of Cape Clear. Situated as it is in the Atlantic Ocean where storms have a two thousand mile fetch in which to generate waves, the tower needed to be exceptionally strong to this end cast iron reinforcing plates bolted together and built around with masonry were used in its construction, despite this it was felt that the tower needed strengthening. A cast iron outer casing was put in place around the original tower to the height of the second floor, the space was infilled with masonry, this was completed in 1868. In 1887 an explosive fog signal was installed in the Fastnet

On 28th November 1881 the lighthouse on Calf Rock in Bantry Bay which was similarly built and reinforced as the Fastnet had the top portion above the reinforcing completely carried away during a storm, no lives were lost. It was therefore decided to replace the Fastnet with one constructed in granite.

The design was by William Douglas, work began in 1899 and proceeded for five years, the resulting tower built in Cornish granite is the tallest and widest rock built lighthouse in both the UK and Ireland. In all the tower is constructed with 2,074 granite blocks weighing between one and three quarter and three tons, each of the blocks are dovetailed into its neighbour the resulting structure is immensely strong, one can only marvel at the skill and tenacity of the workforce who were all employees of the commissioners, the foreman was James Kavanagh, when the light was nearly complete a sudden storm arose which washed some of the equipment away and damaged the optic which was about to be installed.

The new light went into operation on 27th June 1904, the old cast iron light tower was dismantled down to the first floor level and used as an oil store, the fog signal from the old light was transferred to the new, keeping its character of one report every 4 minutes. The optic is four sided it floats in a bath of mercury which allows it to be rotated with the minimum amount of friction, illumination was supplied by two incandescent paraffin burners, in 1834 the horn was changed to once every 3 minutes.

May 1969 saw the end of the oil burners with electric taking their place, the new arrangement had an output of 2,500,000 candelas. The old explosive fog signal was replaced by an electric horn in 1974 this sounds 4 blasts every minute.

March 1989 saw the Fastnet joining the lengthening list of unmanned stations when it was automated, today it is in the care of an attendant and is monitored from the Commissioners facility in Dun Laoghaire County Dublin.

Notable shipping losses in the area was the American packet ship Stephen Whitney near Crookhaven in December 1847. The world famous yacht race named after the rock came to the attention of the world in 1979 when a storm decimated the fleet, resulting in the deaths of 17 of the competitors.