Îlot des Capucins, Military fort on coastal island in Roscanvel, France

The îlot des Capucins is a fortified rocky island that guards the entrance to Brest harbor. The structure uses granite and schist construction with subterranean gun emplacements built into the stone.

Vauban drew up initial defense plans for the site in the late 1600s, yet the actual fortress construction only started in 1848 when engineers modified the rock platform. The 1800s work incorporated newer military requirements of that era.

The island took its name from a nearby rock outcrop that locals saw as resembling a Capuchin monk in prayer. This naming reflects how people connected the landscape to familiar religious figures.

Access to the island is forbidden without authorisation because the site is not secured and carries risks. The 1859 stone arch bridge has lost its protective railings, and crossing it in stormy winds can be difficult. The fort and islet have belonged to the Conservatoire du littoral since 2009.

A trench road serving the works once carried a narrow-gauge railway; a gallery from the north vestibule of the rock-cut magazine leads to a vertical shaft that held a hoist, now gone. The magazine, built around 1890–1892 under 6 to 8 metres of solid rock, supplied every battery in the Capucins group.