Declarations of war during World War II

This is a timeline of formal declarations of War during World War II.

A declaration of war is a formal act by which one nation goes to war against another. The declaration is usually an act of delivering a performative speech (not to be confused with a mere speech) or the presentation of a signed document by an authorized party of a national government in order to create a state of war between two or more sovereign states. The official international protocol for declaring war was defined in The Hague Peace Conference of 1907 (or Hague II).[1] For the diplomatic maneuvering behind these events, which led to hostilities between nations during World War II, see the article entitled Diplomatic history of World War II.

List of war declarationsEdit

Below is a table showing the outbreak of wars between nations which occurred during World War II. Indicated are the dates (during the immediate build-up to, or during the course of, World War II), from which a de facto state of war existed between nations. The table shows both the "Initiator Nation(s)" and the nation at which the aggression was aimed, or "Targeted Nation(s)". Events listed include those in which there were simple diplomatic breaking of relations that did not involve any physical attack, as well as those involving overt declarations or acts of aggression. In rare cases, war between two nations occurred twice, with an intermittent period of peace. The list here does not include peace treaties or periods of any armistice.


Table Legend: Concerning Declaration of War: A = Attack without prior, formal declaration of war; U = State of war arrived at through use of ultimatum;
W = Formal declaration of war made.

Outbreaks of war between nations during World War II
Date Initiator nation(s) Targeted nation(s) Declaration of war: Type Notes/comments Document/event
1939-09-01   Nazi Germany   Poland U[2][3] German attack began at 4:44 a.m., Berlin and Warsaw time.[4][2][5] Invasion
1939-09-01   Slovak Republic   Poland A Invasion
1939-09-03   United Kingdom
  France
  Australia
  New Zealand
  Nazi Germany U[2][3] At 11:15 a.m. London time,[6] British PM, Neville Chamberlain publicly delivered his Ultimatum Speech.[3][7][8] As the Statute of Westminster 1931 was not yet ratified by the parliaments of Australia, and New Zealand, the British declaration of war on Germany also applied to the following dominions. Declaration
1939-09-04   Nepal   Nazi Germany W

Declaration

1939-09-06   South Africa   Nazi Germany W[2][3] Declaration
1939-09-10   Bahrain
  Canada
  Oman
  Nazi Germany W[2][3] Declaration

Declaration

Declaration

1939-09-17   Soviet Union   Poland A[2][3] Invasion
1939-11-30   Soviet Union   Finland A[2][3] Second war between these nations (after Finnish invasion in 1918-1920). Invasion
1940-04-09   Nazi Germany   Denmark
  Norway
A[2] Invasion of Denmark
Invasion of Norway
1940-04-12   United Kingdom   Faroe Islands A[3] Invasion
1940-05-10   Nazi Germany   Belgium
  Netherlands
A/W[2][3] Date of the German offensive in the West, W from Belgium and the Netherlands.[9]

Belgium

Netherlands

1940-05-10   Nazi Germany   Luxembourg A[3] Luxembourg
1940-05-10   United Kingdom   Iceland A Invasion
1940-06-10   Italy   France
  United Kingdom
W[2][3] France and the UK
1940-06-10   Canada   Italy W[2] Declaration
1940-06-11   South Africa
  Australia
  New Zealand
  Italy W[2]

South Africa

Australia

New Zealand

1940-06-11   France   Italy W[2] Declaration
1940-06-25   United Kingdom   Vichy France A Vichy France cuts off diplomatic relations with the United Kingdom on 8 July 1940. Attack
1940-09-09   Italy   Egypt A Egypt maintained neutrality until 1945. Invasion
1940-09-22   Japan   Vichy France A Invasion
1940-09-23   Free France
  United Kingdom
  Australia
  Vichy France A Invasion
1940-10-??   Thailand   Vichy France A Franco-Thai War
1940-10-28   Italy   Greece U[3] Italy invades Greece Invasion
1941-02-05   Free France   Italy A Invasion
1941-04-06   Nazi Germany   Greece W[2][3] Invasion
1941-04-06   Nazi Germany   Yugoslavia A[2][3] Invasion
1941-04-06   Italy
  Hungary
  Yugoslavia A[3] Invasion
1941-04-14   Nazi Germany   Egypt A Egypt maintained neutrality until 1945. Invasion
1941-05-02   United Kingdom   Iraq A Invasion
1941-06-08   Free France   Nazi Germany A Invasion
1941-06-22   Nazi Germany
  Italy
  Romania
  Soviet Union A[2][3] A timed-declaration of war was given by Germany at the time of the attack[10] Invasion
1941-06-22  
Tuva
  Nazi Germany W Tuva was a client state of the Soviet Union. Part of the USSR from 1944.
1941-06-25   Finland   Soviet Union W Finland recognized a state of war with the Soviet Union; third war between these nations. Continuation War
1941-06-27   Hungary   Soviet Union W[3] Invasion
1941-08-25   Soviet Union
  United Kingdom
  Australia
  Iran A Invasion
1941-12-05   United Kingdom   Finland
  Romania
  Hungary
W[11] Declaration
1941-12-07   Japan   United States
  United Kingdom
A[2] W (Japanese point of view); A (British Empire and United States)

Declaration

Attack on Pearl Harbor

Invasion of Malaya

Attack on Singapore

Invasion of Hong Kong

1941-12-07   Canada
  Australia
  New Zealand
  Japan
  Finland
  Romania
  Hungary
W[3]

Canada

Australia

New Zealand

1941-12-07   United Kingdom   Romania
  Finland
  Hungary
W[3] Declaration
1941-12-07   Panama   Japan W[3] Declaration
1941-12-08   United States
  United Kingdom
  Australia
  Costa Rica
  Dominican Republic
  El Salvador
  Guatemala
  Haiti
  Honduras
  Netherlands
  New Zealand
  Nicaragua
  Philippines
  Japan W[3] United States declaration

British declaration
Australian declaration
Costa Rican declaration
Dominican Republic's declaration
Guatemalan declaration
Salvadorian declaration
Haitian declaration
Honduran declaration
Dutch declaration
New Zealand's declaration
Nicaraguan declaration
Philippine declaration

1941-12-08   South Africa   Japan W[3] South African declaration
1941-12-08   China
  Italy
  Japan
W[3] China and Japan had been at war since 1937 Second Sino-Japanese war

Declaration

1941-12-08   Mongolia   Nazi Germany W[citation needed]

Mongolian declaration

1941-12-09   Australia
  New Zealand
  Japan W[3]

Australian declaration

New Zealand's declaration

1941-12-11   Nazi Germany
  Italy
  United States W[2][3]

German declaration

Italian declaration

1941-12-11   United States   Nazi Germany
  Italy
W[2] Germany

Italy

1941-12-11   Poland (in-exile)   Japan W[2] Japan rejected declaration of War. Prime Minister Hideki Tōjō's answer was following: "We don't accept the Polish declaration of war. The Poles, fighting for their freedom, declared war under the British pressure".
1941-12-12   Romania
  Bulgaria
  United States
  United Kingdom
W[3]

Romanian declaration

Bulgarian declaration

1941-12-12   Australia
  Netherlands
  Portugal A Portugal maintained neutrality throughout World War II.

Invasion

1941-12-13   United Kingdom
  New Zealand
  South Africa
  Bulgaria W[3]

British declaration

New Zealand's declaration

South African declaration

1941-12-13   Hungary   United States W[3] Declaration
1941-12-14   Independent State of Croatia   United States
  United Kingdom
W[3] Declaration
1941-12-16   Czechoslovakia (In-exile)   Nazi Germany
  Italy
  Finland
  Romania
  Hungary
  Japan
  Bulgaria
  Independent State of Croatia[12]
W Declaration
1941-12-17   Albania   United States W Declaration
1941-12-20   Belgium   Japan W Declaration
1942-01-01 United Nations Axis Powers W Declared during Arcadia Conference Declaration
1942-01-06   Australia   Bulgaria W Declaration
1942-01-16   Iraq   Nazi Germany
  Italy
  Japan
W Declaration
1942-01-25   Thailand   United Kingdom
  United States
A Declaration
1942-01-25   United Kingdom
  New Zealand
  South Africa
  Thailand W

British declaration

New Zealand's declaration

South African declaration

1942-02-12   Peru   Nazi Germany
  Japan
W Declaration
1942-02-19   Japan   Portugal A Portugal maintained neutrality throughout World War II. Invasion
1942-05-05   South Africa
  Netherlands (in-exile)
  Poland
  Vichy France A Invasion
1942-05-05   United Kingdom
  Northern Rhodesia
  Southern Rhodesia
  South Africa
  Tanganyika
  Belgian Congo
 
  Japan
A Invasion
1942-05-22   Mexico   Nazi Germany
  Italy
  Japan
W[3] Declaration
1942-06-13   Iroquois Confederacy   Nazi Germany
  Italy
  Japan
W Only Native American tribe to have declared war on the Axis powers separately from the United States. Announced on the steps of the U.S. Capitol by a representative that "a state of war exists between our Confederacy of Six Nations on the one part and Germany, Italy, Japan and their allies against whom the United States has declared war, on the other part." Declaration
1942-08-22   Brazil   Nazi Germany
  Italy
W Declaration
1942-11-08   United States
  Canada
  Vichy France Vichy France A Invasion
1942-11-10   Nazi Germany
  Italy
  Vichy France A Invasion


1942-12-14   Ethiopia   Nazi Germany
  Italy
  Japan
W On 3 October 1935, Italy invaded Ethiopia without a formal declaration of war. In response to the Italian invasion, Ethiopia declared war on Italy. Most of Ethiopia was occupied by Italy in 1936, however parts of Ethiopia remained under the control of the Ethiopian Patriots Movement, which begun its guerrilla war against the occupying Italian forces the day Addis Ababa fell in May 1936. In May 1941, Addis Ababa was liberated by the Gideon Force, restoring sovereignty to Ethiopia. Second Italo-Ethiopian War

Declaration

1943-01-20   Chile   Nazi Germany
  Italy
W President Juan Antonio Ríos officially suspended all trade and diplomatic relations with the Axis powers, and Chile officially joined the Allies as authorities began rooting out Nazi spies from Operation Bolivar. While Chile would officially declare war on Japan in 1945, the American government and international press celebrated this day as Chile declaring war on the Axis. Declaration
1943-04-02   Bolivia Axis powers W Bolivia officially joined the Allies on 7 April 1943. Shortly after war was declared, the President, Enrique Peñaranda, was overthrown in a coup. Bolivian mines supplied needed tin to the Allies, but no troops or warplanes were sent overseas. Bolivians remained confident their geographic isolation would protect them from the war. Declaration
1943-09-01   China Regime of Wang Jingwei Allied Powers W Declaration
1943-09-09   Iran   Nazi Germany W Declaration
1943-10-13   Italy   Nazi Germany W[2] Italy had changed sides after the fall of Mussolini. The Declaration of War was given by Pietro Badoglio to the German ambassador in Madrid.[2] Declaration
1943-11-26   Colombia   Nazi Germany W See Colombia during World War II Declaration
1944-01-17   Free France   Italian Social Republic A Invasion
1944-01-27   Liberia   Nazi Germany
  Japan
W Declaration
1944-06-06
  France
  Nazi Germany A Invasion
1944-07-25
  France
  Japan A Invasion
1944-08-25   Romania   Nazi Germany
  Hungary
W Romania switched sides Declaration
1944-09-05   Soviet Union   Bulgaria W Declaration
1944-09-08   Bulgaria   Nazi Germany W Bulgaria switched sides Declaration
1944-09-15   Nazi Germany   Finland A Lapland War
1944-09-23   Second Philippine Republic   United States
  United Kingdom
W[13] Philippine declaration
1944-12-31   Hungary   Nazi Germany W[14] Hungary switched sides Declaration
1945-02-02   Ecuador   Nazi Germany
  Japan
W Ecuadorian declaration
1945-02-07   Argentina
  Paraguay
  Nazi Germany
  Japan
W

Argentinean declaration

Paraguayan declaration

1945-02-15   Venezuela
  Uruguay
  Nazi Germany
  Japan
W

Venezuelan declaration

Uruguayan declaration

1945-02-21   San Marino   Nazi Germany W Declaration
1945-02-23   Turkey   Nazi Germany
  Japan
W Declaration
1945-02-24   Egypt   Nazi Germany
  Japan
W Declaration
1945-02-26   Syria
  Lebanon
  Nazi Germany
  Japan
W Declaration
1945-03-01   Saudi Arabia   Japan W Declaration
1945-03-03   Finland   Nazi Germany W Finland switched sides Lapland War
1945-04-11   Chile   Japan W Declaration
1945-07-06   Brazil   Japan W Declaration
1945-07-09   Norway   Japan W Declaration[15]
1945-07-14   Italy   Japan W Declaration
1945-08-08   Soviet Union   Japan W[2] Last outbreak of war during the entire Second World War. Declaration
1945-08-10   Mongolia   Japan W[16] W (de jure) A (de facto 1945-08-09) War declared 24 hours after crossing the border with Soviet troops

Soviet Invasion of Manchuria Mongolia in World War II

Literature about the warEdit

  • Harman, Nicholas (1990). Dunkirk: the Necessary Myth. Jove. ISBN 978-0340517857.
  • German White Book. All World Wars.
  • Hitler, Adolph (2012). The Great Tragedy: Germany's Declaration of War against the United States of America. ISBN 978-1300127703.
  • Torrie, Julia S. (2010). "For Their Own Good": Civilian Evacuations in Germany and France, 1939–1945. Berghahn Books. ISBN 978-1845457259.

ReferencesEdit

  1. ^ On the Opening of Hostilities; 1907; Yale Law School Library; retrieved March 2014.
  2. ^ a b c d e f g h i j k l m n o p q r s t u v w "2194 Days of War"; (1977); Salmaggi, C. & Pallasvini, A.; ISBN 91-582-0426-1; per tables included. [Italian; American]
  3. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad Timeline Data Archived May 5, 2016, at the Wayback Machine; World at War online; retrieved February 2014.
  4. ^ "Germans invade Poland". History.com. Retrieved 1 Dec 2019.
  5. ^ On This Day
  6. ^ Mann, Andrea. "September 3, 1939: Britain declares war on Germany after Hitler's troops invade Poland". BT.com. Retrieved 1 Dec 2019.
  7. ^ Note: Included in the speech: "...This morning, the British Ambassador in Berlin handed the German Government a final note, stating that unless we heard from them by 11 O'clock that they were prepared at once to withdraw their troops from Poland a state of war would exist between us. I have to tell you now that no such undertaking has been received and that consequently this country is at war with Germany..."
  8. ^ 1939: Britain and France declare war on Germany, BBC
  9. ^ Swedish Encyklopedia; "Bonniers Lexikon" (Vol. 1); (c.1960s); table in article by Andra Världskriget: The Second World War; Pp. 461-462.
  10. ^ "The Rise and Fall of the Third Reich"; Shirer, William L
  11. ^ Declaration of War on Finland, Hungary and Romania
  12. ^ all countries at war with the United States, United Kingdom, or the Soviet Union
  13. ^ [1]
  14. ^ Hungary declares war on Germany
  15. ^ https://trove.nla.gov.au/newspaper/article/2634950
  16. ^ Christopher P. Atwood (1999), "Sino-Soviet Diplomacy and the Second Partition of Mongolia, 1945–1946", Mongolia in the Twentieth Century: Landlocked Cosmopolitan, Bruce A. Elleman and Stephen Kotkin, eds. (Armonk, NY: M. E. Sharpe), 147.