Which strait separates mainland Greece from the island of Euboea?

The Euripus Strait separates mainland Greece from the island of Euboea. It is a narrow tidal channel beside the city of Chalkida, where a bridge crosses between the mainland and the island.

The channel is famous for unusual tidal currents that reverse direction several times a day. These currents are driven by local tidal conditions and the shape of the surrounding Gulf of Euboea. The changing flow has attracted scientific curiosity since antiquity.

Ancient writers discussed the strait’s currents, and Aristotle was traditionally said to have been puzzled by them, although the story is not firmly established as historical fact. The Euripus is not the same as the Strait of Otranto or the Dardanelles: it is a local Greek channel within the Aegean region, rather than a major inter-basin gateway.