- The Bay of Biscay (/ˈbɪskeɪ, -ki/ BISS-kay, -kee) also known as the Gulf of Biscay or the Gulf of Gascony is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the northern coast of Spain, extending westward from the French border to Cape Ortegal, and along the western coast of France from Point Penmarc’h southward to the Spanish border.