The Sandwich Tern breeds mainly on or near coasts around Europe including the Black Sea and Caspian Sea and along the Atlantic coasts of North and South America. West European birds winter mainly on the west coast of Africa as far south as the Cape of Good Hope tending to leave in late September and return in late March. Some North American birds winter in South America. Cuba has both breeding birds and winter migrants.

They are strictly coastal and feed almost entirely off fish which they catch by plunge-diving from up to 10 metres above the surface of the sea. The second photo shows the bird hovering while looking for prey while the 3rd photo shows an adult carrying fish back to the nest.

There is an illustration in HBW, Volume 3, Page 644.