This is a timeline for the Battle of the Atlantic (1939–1945) in World War II.
August 19, 1939
August 21, 1939
August 24, 1939
September 3, 1939
September 5, 1939
September 7, 1939
September 14, 1939
September 16, 1939
September 17, 1939
September 17, 1939
September 20, 1939
September 26, 1939
September 30, 1939
October 5, 1939
October 14, 1939
October 16, 1939
October 27, 1939
October 30, 1939
November 21, 1939
November 23, 1939
November 25, 1939
December 4, 1939
December 5, 1939
December 10, 1939
January 30, 1940
February 5, 1940
February 14, 1940
March 16, 1940
June 12, 1940
June 14, 1940
June 22, 1940
June 25, 1940
June 30, 1940
July 2, 1940
July 4, 1940
July 8, 1940
July 10, 1940
July 17, 1940
July 26, 1940
July 31, 1940
August 4, 1940
August 5, 1940
August 15, 1940
August 16, 1940
August 23, 1940
August 24, 1940
August 25, 1940
August 28, 1940
August 30, 1940
August 31, 1940
September 2, 1940
September 4, 1940
September 6, 1940
September 8, 1940
September 15, 1940
September 17, 1940
September 18, 1940
September 20, 1940
September 21, 1940
September 26, 1940
September 27, 1940
September 28, 1940
October 9, 1940
October 11, 1940
October 14, 1940
October 15, 1940
October 17, 1940
October 18, 1940
October 19, 1940
October 22, 1940
November 5, 1940
November 6, 1940
November 15, 1940
November 21, 1940
November 22, 1940
November 23, 1940
December 1, 1940
December 11, 1940
December 27, 1940
January 16, 1941
January 29, 1941
February 12, 1941
February 19, 1941
February 24, 1941
February 26, 1941
February 27, 1941
March 1, 1941
March 7, 1941
March 8, 1941
March 13, 1941
March 16, 1941
March 17, 1941
March 19, 1941
March 29, 1941
April 1, 1941
April 3, 1941
April 6, 1941
April 9, 1941
April 16, 1941
April 28, 1941
May 8, 1941
May 11, 1941
May 14, 1941
May 20, 1941
May 21 or 22, 1941
May 24, 1941
May 27, 1941.
June 1, 1941
June 11, 1941
June 13, 1941
June 24, 1941
June 26, 1941
July 7, 1941
August 5, 1941
September 10, 1941
September 15, 1941
September 19, 1941
September 22, 1941
October 16, 1941
October 21, 1941
October 31, 1941
November 3, 1941
December 10, 1941
January 12, 1942
January 30, 1942
February 10, 1942
February 15, 1942
February 16, 1942
March 20, 1942
May 12, 1942
June 10, 1942
July 4, 1942
July 5, 1942
July 6, 1942
August 8, 1942
August 15, 1942
August 16, 1942
August 17, 1942
August 19, 1942
August 22, 1942
August 28, 1942
August 31, 1942
September 9, 1942 USS Muskeget, a Coast Guard weather ship, is torpedoed near Weather Station #2, Lat. 54o N, Long 44o 30’W by U-755. 121 Officers and crew lost, including one Public Health Service officer and four weathermen, no survivors.
September 14, 1942
September 20, 1942
September 22, 1942
October 4, 1942
October 13, 1942
October 14, 1942
October 24, 1942
October 25, 1942
October 27, 1942
November 2, 1942
November 18, 1942
December 8, 1942
January 3, 1943
January 8, 1943
January 13, 1943
January 17, 1943
January 26, 1943
February 2, 1943
February 7, 1943
February 15, 1943
March 7, 1943
March 10, 1943
March 16, 1943
March 28, 1943
April 4, 1943
April 12, 1943
April 17, 1943
April 22, 1943
May 6, 1943
May 7, 1943
May 11, 1943
July 31, 1943
September 8, 1943
October 9, 1943
October 31, 1943
December 26, 1943
April 6, 1944
July 20, 1944
August 3, 1944
September 8, 1944
January 27, 1945
March 2, 1945
April 18, 1945
Total Allied losses to mines during 1939 are 79 vessels totaling 262,700 tons.