Strumble Head Lighthouse stands imposingly on St. Michael's Island (Ynysmeicl), an islet to the west of Fishguard, separated from the mainland by a very narrow gap through which the sea boils and froths in stormy weather.

The station was built in 1908 by Trinity House for the greater safety of sea traffic between Ireland and the new Fishguard Harbour which is located behind cliffs and a breakwater three miles to the east. The new light also formed a link with the existing South Bishop light, 29 km (18 miles) to the south-west. This stretch of coast is very dangerous, and some sixty vessels are known to have been lost along it in the 19th Century alone.

The original revolving lens system weighed 4½ tonnes, supported in a bath of mercury to reduce friction. A massive clockwork mechanism rotated it, driven by a 0.25 tonnes weight which, suspended on a cable, dropped gradually down a cylinder running from top to bottom through the tower and had to be re-wound every twelve hours. The optical system was replaced by more compact equipment when Strumble Head lighthouse was fully electrified in 1965.

Despite the footbridge to the mainland across the narrow sound, Ynsymeicl's isolation and steep slopes set building problems typical of more remote rock towers. Building material and regular supplies were swung across by jackstay cable, between the winches near the cliff-top on the mainland and beside the lighthouse. The handrail of the footbridge and the steps to it also had a special purpose, as the pipeline to carry oil into the tower basement.

The lighthouse was converted to unmanned automatic operation in 1980.