The Bay of Biscay is a gulf of the northeast Atlantic Ocean south of the Celtic Sea. It is along the western coast of France from Brest south to the Spanish border, and the northern coast of Spain west to Cape Ortegal. It is named in English after the province of Biscay, in the Spanish Basque Country.

The average depth is 1,744 metres (5,722 ft) and maximum depth is 2,789 metres (9,150 ft).

Spanish coast along the Bay of Biscay