Agios Efstratios has many small and secluded beaches. At the south part of the island and 5 km from the settlement you will find Agios Antonios, a small beach with sand and pebbles, where you can sit under the shade of oak trees. The more frequented beach of Agios Dimitrios is found to the same direction. A bit further you can visit the more secluded sandy beach of Trygaris but at some point you have to leave your car and continue on foot in order to reach it. Southwest, in a small cove you will find the pretty beach of Fragou. The beach Trypiti has the same morphology but it is bigger and you will also have to walk for a while in order to arrive there. On the west part of the island you will find Lidario. It is a wide sandy beach which requires a 5-minute walk from the end of the road. The beach Ftelio is also located on the west, close to Lidario, and is sandy with no shade. The largest beach of the island, Alonitsi, is located on the northeast. It is a sandy beach with shallow waters and the skerry of Velia is located at a close distance.

If you do not want to leave the settlement you can enjoy swimming at the beautiful waters of the volcanic beach of Arkari with the grey pebbles, next to the small harbor of the island, with a wonderful view to the sunset. And if you own a boat you can also discover many more beaches which are not easily accessible by land, visit the numerous skerries such as Dodeka Apostoloi, Daskalio, and Velia and explore the sea caves of the island which offer shelter to the Mediterranean Monk seals Monachus monachus.