The Battle of the Atlantic was the longest running campaign of the Second World War, beginning in 1939 and continuing through until the end of the war in 1945.

It was essential that Britain, as a island nation, maintained good shipping routes across the Atlantic in order that essential supplies and cargo be transported from the Americas to British ports. The Germans attempted to thwart these ships with the use of U-Boats, the Kreigsmarine and the Luftwaffe. In contrast to land battles the front was large and ever-changing, and although the U-boats were largely defeated by 1943 the campaign continued to be waged until the war's end.