The islands are directly administered by the French government, and form a protected nature reserve with restricted access. Mooring is allowed between the 2 islands.
A light is shown from a square tower, 17m high, standing on Ile du Large, the NE island. Ile de Terre, lying 0.3 mile SW, is a bird sanctuary and landing is prohibited.
In very clear weather, these islands can be easily distinguished. A submarine cable extends SW from the islands to the mainland and may best be seen on the chart.
An extensive area of shallow shoal banks, lying parallel to the coast and separated from the coastal dangers, extends about
5 miles NW and about 6 miles ESE of the Iles Saint-Marcouf.
This shoal area is marked by lighted buoys. A channel leads between this extensive area of shoal banks and the mainland shore. However, due to the numerous wrecks lying in this vicinity, local knowledge is advised.