Marianne Island is a small granitic island of the Seychelles. It is located 3.8 km ESE of Felicite Island. The island was a former coconut plantation, and on the western side of the island is a long beach. The southern tip of Marianne is known as a world-class diving location. The tallest peak on the island is Estel Hill at 130 meters.
Presently, Marianne Island is uninhabited but is routinely visited by tourists and boaters. For much of the 19th and 20th century, farming and copra production took place on Marianne. There was a former settlement called La Cour, and in 1940 the island had 60 inhabitants.
There are a few species of gecko on Marianne, including the La Digue day gecko and Phelsuma astriata semicarinata. Reportedly, the rare Seychelles paradise flycatcher is occasionally spotted on the island. Also, it was once home to the extinct Seychelles chestnut-sided white-eye.