The island of Marathonisi is close to Laganas bay. A place worth to visit, where the nesting area of Caretta-Caretta can be spoted. Amazingly, it has the shape of a turtle. The vegetation is thick with pine-trees and green oak trees. There are two beaches to visit in Marathonissi. The one on the side hosting golden sand where the turtle Caretta Caretta lay their eggs, while on the second you will find a beach with pebbles and two small accessible sea caves. To visit Marathonissi, you can rent a boat from Keri Lake or Laganas bay. The area is protected by The national Marine Park, as it is one of the shelters of Caretta Caretta sea turtle. Access is restricted at certain times and staying overnight on the islet not allowed.
Access to Marathonisi Island can be done by boat. It is not accessible for people with disabilities, unless you prefer to stay on the boat and not swim.
Map it here https://goo.gl/maps/3odHxyTLrUw