Atalanti or Atalantonisi (Αταλαντονήσι) or Talandonísi (Ταλαντονήσι) is a small uninhabited island in the North Euboean Gulf, about 600 m off the coast near the town Atalanti, Phthiotis, Greece. There are several small islets next to Atalanti island, including the islet of Agios Nikolaos.