Mathraki
As you come into the main port Plakes on the left side the beach is sandy and very long sand dunes. We was there in August 2016 and a lot of naturists will go again.
September 2018 - Lots of opportunities for naturism all over this small island. The end of the long sandy beach south of Plakes gives some privacy. There were only a handful of tourists on the island when we were there. Some opportunity for nude walking at the north end.
There is also nearby Erikoussa Island and Brakini beach on the east coast is completely empty and long naked days are fantastic there. Again, there are opportunities for nude walking in the hills.