Air Operations, Europe

There are heavy RAF night attacks on Hamburg and Bremen.

Balkans

The Germans complete their occupation of the Aegean Islands.

Battle of the Atlantic

• U-110, commanded by Fritz Julius Lemp, sinks from the depth charge damage received on May 9 while on the way to Iceland. Throughout the war the Germans do not discover that U-110 has been captured. (It should be noted that the code details captured do not include the main code which will be used by the Bismarck. None of the Bismarck's messages will be successfully decoded by the British at the time.)
• U-103 sinks the British steamer City of Shanghai (5828t) west of Freetown with the loss of 6 crewmen. 67 survivors are picked up by the Dutch steamer Stad Arnhem, the British steamer Richmond Castle and the Argentinian steamer Josefina S..
• The British steamer Somerset (8790t) is sunk by German bombing west of Ireland. The entire crew is rescued.

United States, Home Front

Former President Herbert Hoover says only by staying out of the war can the U.S. aid Britain. He also says that America is unprepared even for an adequate defense and that the American people are not united. He predicts that an invasion of Europe will require 5 million U.S soldiers.