Cranae or Kranai (Greek: Κρανάη [kraˈnai]) (also Marathonisi) is an island off the coast of Gytheio (ancient Gythium) connected to the land by a causeway built in 1898.

[1] When Gythium became the major port of ancient Sparta, Cranae became a resting spot for traders.

When Greece became a part of the Ottoman Empire, the beys of Mani fortified Cranae with a Maniot tower.

On the island there is a chapel dedicated to St Peter (Agios Petros) which is favored by many couples to use on their weddings due to its beautiful views of the city of Gytheio and picturesque location.

There is also a prominent 23m-high lighthouse built in 1873 with high-quality marble from the area of Tainaro in south Mani peninsula.