Timeline of events in the Pacific War
1939
- 14 June: Japanese blockade British concession at Tientsin, China
- 22 August: Soviet Union and Germany sign non-aggression pact
- 1 September: Germany invades Poland
- 3 September: Britain, France, New Zealand and Australia declare war on Germany
- 12 September: Enlistment for 2 New Zealand Expeditionary Force (2 NZEF) begins
- 3 October: First Echelon, 2 NZEF training begins at Burnham, Trentham, Hopuhopu and Papakura
- 23 November: Major-General Bernard Freyberg is appointed to command 2 NZEF
- 13 December: Battle of the River Plate - New Zealand cruiser HMS Achilles involved in battle with German pocket battleship Admiral Graf Spee
1940
- 5 January: First Echelon embarks for the Middle East
- 5 June: New Zealand begins raising an infantry brigade group for Fiji
- 10 June: Italy declares war on Great Britain and France
- 11 June: Australia, New Zealand and South Africa declare war on Italy
- 20 August: German raider Orion sinks the steamer Turakina off Cape Egmont
- 10 September: Advance party of 8 Infantry Battalion leave for Fiji
- 27 September: Tripartite (Axis) Pact signed by Germany, Italy and Japan
- 3 November: HQ 8 Infantry Brigade established in Fiji
- 25 November: Steamer Holmwood sunk by German raiders off Chatham Islands
- 27 November: Rangitane sunk by German raiders 480km from East Cape
- 8 December: New Zealand steamer Komata sunk by German raiders off Nauru Island
1941
- 3 March: Bulk of 2 NZEF now in the Middle East
- 25-27 July: Britain, Australia, New Zealand and United States freeze Japanese assets
- 28 July: Japanese troops move into southern Indo-China
- 18 October: General Tojo Hideki forms Cabinet in Japan
- 7 December: Japanese attack Pearl Harbor
- 7 - 8 December: Japanese troops land in Thailand and north-eastern Malaya
- 8 December: Britain, USA, and New Zealand declare war on Japan
- 18 December: Japanese land in Hong Kong
- 22 December: Japanese land in the Philippines
- 23 December: New Zealanders serving with 67 Squadron RAF have first encounter with enemy during Japanese air raid on Rangoon, Burma
- 25 December: Hong Kong falls to Japanese troops
- 31 December: Martial law declared in Singapore
1942
- 2 January: Japanese occupy Manila
- 3 January: 488 (NZ) Sqn RAF in action at Singapore
- 10 January: More New Zealand reinforcements to Fiji
- 30 January: Japanese within 25 km of Singapore
- 8 February: Japanese invade Burma
- 10 February: US naval vanguard arrives in Wellington
- 15 February: Fall of Singapore
- 19 February: Japanese attack Indonesia; Darwin, Australia, raided for the first time
- March: Japanese air raids over Australia
- 8 March: Japanese submarine I-25 sends reconnaissance plane over Wellington
- 13 March: Reconnaissance flight from I-25 over Auckland
- 18 April: US General Douglas MacArthur assumes command of the South West Pacific Area; New Zealand in South Pacific Area a US Navy responsibility under Admiral Chester Nimitz
- 7 – 8 May: Battle of Coral Sea; Japanese forces heading for Port Moresby turn back
- 31 May: Japanese midget submarine raid on Sydney Harbour
- 3-6 June: US victory at Battle of Midway effectively ends the danger of invasion of New Zealand
- 12 July: New Zealand freighter Hauraki captured by a Japanese raider
- 24 July: US assume control in Fiji; 2 NZEF troops in Fiji return to New Zealand
- July: 9 Sqn RNZAF deployed to New Caledonia
- 7 August: First US land offensive against Japan at Guadalcanal in the Solomon Islands
- September: HMNZS Leander involved in Solomons campaign
- 5 – 13 October: US forces continue attacks against Japanese at Guadalcanal
- 15 October: Seventeen New Zealand coastwatchers and five civilians captured in the Gilbert Islands (now Kiribati) beheaded at Betio, Tarawa
- October: 3 Sqn RNZAF deploys in South Pacific theatre
- 2 December: Professor Enrico Fermi sets up an atomic reactor in Chicago
- 3 December: 3 NZ Div HQ temporarily established in New Zealand; throughout December troops NZ troops sent to New Caledonia
1943
- 5 January: HMNZS Achilles badly damaged by bomb off Guadalcanal
- 22 January: Australian and US forces defeat Japan in the Papua campaign
- 29 January: Japan withdrawing land forces from Guadalcanal
- 29 – 30 January: RNZN corvettes Kiwi and Moa sink Japanese submarine I-1 off Guadalcanal
- 18 May: Japan begins an offensive along Yangtze River
- 20 May: New Zealand government agrees to keep 2 NZEF in the Middle East to be available for operations in Europe; 3 Division in the Pacific to be reduced
- 12 – 13 July: HMNZS Leander suffers heavy damage when torpedoed off New Georgia
- 15 August: US troops land at Vella Lavella in the Solomon Islands
- 16 August: Heavy Allied air attacks on Japanese at Wewak, Papua New Guinea
- 3 October: 3 NZ Division secures Vella Lavella
- 5 October: US force attacks Wake Island
- 27 October: 3 NZ Division lands on Mono in the Treasury Islands
- 1 November: US invades Bougainville
1944
- January: US invades Marshall Islands
- 15 – 18 February: 3 NZ Division lands on Nissan Island; organised Japanese resistance ceases by 20 February
- 29 February: US General Douglas MacArthur's force invades Admiralty Island
- 7 March: 20 New Zealand aircraft take part in attack on Rabaul
- 8 May: Japanese launch offensive against British troops in Burma
- 15 June: Main body of 3 NZ Division HQ returns to New Caledonia
- 16 June: China-based B-29s bomb southern Japan
- 21 July: US troops land in Guam
- 10 August: Japanese resistance in Guam ends
- 20 October: Philippines campaign begins
- 5 November: Allied planes bomb Singapore
- 24 November: B-29s bomb Tokyo
- 24 December: Last Japanese attack on Calcutta
1945
- 22 January: Burma Road is reopened
- 19 February: US troops land on Iwo Jima, Japan
- 21 March: British forces take Mandalay, Burma
- 1 April: US troops invade Okinawa
- 3 May: Rangoon recaptured
- 13 May: Australian troops occupy Wewak
- 26 May: 700,000 incendiary bombs fall on Tokyo
- 8 May: VE Day (Victory in Europe)
- 1 June: First landing of US troops on Okinawa
- 20 June: Australian troops land in Sarawak
- 21 June: US forces capture Okinawa
- 5 July: Liberation of the Philippines completed
- 14 July: US Navy bombards Honshu and Hokkaido
- 16 July: First atomic bomb test in New Mexico
- 3 August: Japanese home islands blockaded
- 6 August: Atomic bomb dropped on Hiroshima, Japan
- 8 August: Russia declares war on Japan
- 9 August: Atomic bomb dropped on Nagasaki, Japan
- Soviet troops enter Manchuria
- 12 August: Soviet troops enter Korea
- 14 August: Japan accepts Allied surrender terms
- 15 August: VJ Day (Victory in Japan)
- 28 August: US troops enter Japanese main islands
- 30 August: British troops re-occupy Hong Kong
- 2 September: Formal Japanese surrender on deck of USS Missouri