Fort-Bloqué, Tidal island castle in Ploemeur, France.

Fort-Bloqué is a military fortress built on a rocky outcrop off the Breton coast, completely cut off by seawater during high tide and accessible on foot when the tide recedes. The stone structure sits exposed on this small island and forms a striking part of the coastal landscape.

The fortress was built in 1758 in response to British naval attacks, serving as a defensive post to protect the strategic harbor of Lorient. This construction was part of a broader coastal defense system developed during the 18th century.

The fort represents the military engineering of 18th century France, demonstrating the strategic importance of protecting maritime access to the port of Lorient.

Visit this site at low tide when you can reach it on foot and examine the fortress up close without getting wet. Check the tide tables before going to avoid being caught off guard by rising water.

The fort's popular name dates from 1871, when a curved wall closed the open horseshoe battery and turned it into a small stronghold; people then called it Fort-Bloqué, the "blocked fort". The name later passed to the village built opposite after the D 152 road opened the area in the 1950s.