Marathonisi is a small and hilly privately-owned islet, located one nautical mile off the coast of Zakynthos, across from Limni Keri beach. It had permanent inhabitants until the Second World War, but today no settlement or construction is allowed on it. As a result, the hills are covered in thick pine, olive and green oak forests. This islet forms part of the National Marine Park of Zakynthos. The park was established in 1999 to protect the breeding grounds of the loggerhead sea turtles (Caretta caretta) and Marathonisi is one of the most important breeding sites for this endangered species.