The Temple of Poseidon is located near the Church of the Prophet Elias, at the north-western side of Poros.

Located on a hill overlooking the beach of Vagionia, the site includes the foundations of the sea god’s temple, and other major findings such as the arches of the ancient village market and the Asclepeion, also known as the monument to famed Athenian orator Demosthenes.

Excavations began in the late 19th century and continue today, though the full extent of the ancient village surrounding the temple is still an open question, following the discovery of the ancient city of Kalavria.