If you like diving, Agios Efstratios offers a unique diving experience, since at its seabed you will have the chance to see the underwater meadows of Posidonia seagrass, a place of habitation and reproduction for many marine organisms, contributing at the same time to the coastal protection and erosion.
Well-known diving spots are the nearby skerries such as Dodeka Apostoloi on the north of the island. The seabed of the area is characterised by high turnover of depth and relief and offers a variety of substrate and habitats (reefs, seagrass, small caves, sandy areas etc.).
Info: http://www.diveinourislands.com/en-us/Lesvos-Lemnos