Sémaphore de la Pointe Saint-Mathieu, Maritime traffic control point in Plougonvelin, France

The Sémaphore de la Pointe Saint-Mathieu is a square, tapering tower with a white facade and grey stone quoins, standing beside dark water on the Brittany coast at Plougonvelin. Four levels with small rectangular windows rise above a lower stone base, topped by a glazed observation deck, a flat roof, a metal railing and a mast with a flag. The watch room is reached by 92 steps.

A first semaphore was set up in 1861 east of the present site, between the abbey and the Rospects cliffs, but it lacked a view of the Four Passage. A new 39-metre tower was built at the current location in 1906. From 15 September 1962 the station operated around the clock with a crew of six, and the watch room was rebuilt between 1972 and 30 May 1973.

The semaphore is one of a chain of 52 coastal surveillance posts operated by the French Navy. Its watch room, reached by 92 steps, listens to distress frequencies and keeps optical watch over the sea area; the station also serves meteorology. Flag signals once communicated with passing ships, with messages relayed onward by telegraphy.

The location functions as a watch point for vessels and boats traveling in the area. Visitors should be aware that this is an active operating facility and access or tours may be restricted.

The station covers 920 m² and belongs to a chain of 52 coastal surveillance posts run by the French Navy. Its crews listen to distress frequencies, watch the sea visually and supply meteorological data, while the watch room is reached by 92 steps.