The Antarctic Campaign of World War II is a lesser known but nevertheless important military expedition during the war. Germany sent an expedition to Antarctica in 1938 to establish a whaling base for the newly created German whaling fleet to allow for more materials like fats and oils to increase production, rather than the usual German reliance on oils and fats from the Norwegian whaling industry. However, the expedition only was able to bring about a small German base in New Swabia and certain outposts around the Antarctic coast.
In 1939, the United States sent an expedition to Antarctica in order to combat the German expedition to the continent a year earlier in a search to create a permanent US settlement in Antarctica. However, the expedition fared better than the German one in 1938, and the US was able to construct two bases, West Base and East Base near Charot Island and King Edward VII land respectively. However, when World War II broke out on September 1st, 939, and with the Japanese attack on Pearl Harbor on December 7th, 1941, all personnel from the two bases were evacuated in order to strengthen US focus on the war effort rather than their pre-wartime expedition.
The Germans continued to use their outposts in Antarctica as stopping points for German tankers and auxiliary vessels carrying food, supplies, and other materials. Thus, with the war ramping up, particularly in the Atlantic, the German outposts in Antarctica served as crucial points for not only German commerce, but submarine warfare. Submarine warfare by the Germans inflicted heavy casualties and loss of valuable material on Allied shipping, and at the time (1940-1942), the US Navy was in a tense standoff with the Japanese Navy in the Pacific, so there was little US support in protecting allied convoys and ships. In addition, with Britain focused on holding onto their colonies around the world, and their war on the home front, Allied commerce suffered early in the war.
In 1943, Britain, in an attempt to lessen the effect of submarine threats on Allied shipping, secretly authorized Operation Tabarin, in which the British would send a military expedition to Antarctica in search of German submarine bases and other German outposts. Surprisingly, the expedition found no trace of any German presence in Antarctica, and simply only found materials and abandoned outposts left behind by the earlier Argentine expedition to Antarctica earlier that same year. Subsequently, the British left their main port in Antarctica, Port Foster, and refocused their efforts on the rest of the war. However, the British maintained a presence in Antarctica until 1946, when Operation Hi-Jump, authorized by the US Navy, sought to establish an Antarctic research base.
For the rest of World War II, the Germans continued to use their secret submarine outposts in Antarctica, hidden from the British expedition, to continue causing havoc to Allied shipping not only in the Atlantic, but around the world. However, at the end of the war, Germany evacuated all submarine bases and outposts, and the Antarctic Campaign of World War II ended.