Atlas of Battles

battle, interwar and Second World War

Battle of Sio

Battle of Sio was a battle fought on 5 December 1943 at Sio, in what is now Papua New Guinea; it lasted 3 months. It was part of the Pacific War, which ran from 1941 to 1945. The recorded result: Allied victory. Recorded strength: ~15,000 against ~8,000.

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Members of "B" Company, 30th Infantry Battalion crossing a shallow creek between Weber Point and Malalamai. They have been advancing from Roinji over muddy swamps, Kunai grass and innumerable riers to
Members of "B" Company, 30th Infantry Battalion crossing a shallow creek between Weber Point and Malalamai. They have been advancing from Roinji over muddy swamps, Kunai grass and innumerable riers to. Buchanan, Robert John, Public domain, via Wikimedia Commons.
Fought5 December 1943lasted 3 months
WhereSio, Papua New Guinea5.955S, 147.370E
OutcomeAllied victory
BelligerentsAustralia; Papua; United StatesagainstEmpire of Japan
Casualties and losses83 killed; 186 woundedand1,421 killed; 2,198 found dead; 76 captured
Part ofPacific War1941 to 1945

Where it sits in the Pacific War

Bombing of Tokyo, 1940Bombing of South-East Asia, 1940Japanese invasion of French Indochina, 1940Battle of Guam, 1941Bombing of Bangkok in World War II, 1941Shelling of Johnston and Palmyra, 1941Axis and Soviet air operations during Operation Barbarossa, 1941Attack on Pearl Harbor, 1941Philippines Campaign, 1941Battle of Hong Kong, 1941Battle of Wake Island, 1941Dutch East Indies campaign, 1941Bombing of Singapore, 1941Battle of Prachuap Khiri Khan, 1941Japanese invasion of Batan Island, 1941Attack on Clark Field, 1941Sinking of Prince of Wales and Repulse, 1941Japanese invasion of Aparri, 1941Japanese invasion of Vigan, 1941Battle of Jitra, 1941Japanese invasion of Legazpi, 1941Battle of Gurun, 1941Battle of Borneo, 1941Japanese Invasion of Davao, 1941Battle of Piis, 1941Battle of Kampar, 1941Solomon Islands Campaign, 1942Burma Campaign, 1942Battle of Savo Island, 1942Battle of Rabaul, 1942Battle of Corregidor, 1942Invasion of Tulagi, 1942Battle of Java, 1942Battle of Tarakan, 1942Japanese invasion of Cotabato, 1942Bombing of Mandalay, 1942Battle of Slim River, 1942Battle of Bataan, 1942Battle of Manado, 1942Battle of Kuala Lumpur, 1942Battle of Muar, 1942Battle of Gemas, 1942New Guinea campaign, 1942Battle of Balikpapan, 1942Battle of Ambon, 1942Marshalls–Gilberts raids, 1942Battle for Australia, 1942Battle of Port Moresby, 1942Battle of Makassar Strait, 1942Battle of Singapore, 1942Battle of Kranji, 1942Battle of Sarimbun Beach, 1942Battle of Bukit Timah, 1942Battle of Palembang, 1942Battle of Pasir Panjang, 1942Battle of Badung Strait, 1942Bombing of Darwin, 1942Battle of Timor, 1942Air raids on Australia, 1942–43, 1942Bombardment of Ellwood, 1942Wake Atoll raid, 1942Battle of Los Angeles, 1942Battle of the Java Sea, 1942Battle of Sunda Strait, 1942Second Battle of the Java Sea, 1942Attack on Broome, 1942Operation K, 1942Bombing of Sukabumi, 1942Battle of Tjiater Pass, 1942Invasion of Salamaua–Lae, 1942Invasion of Sumatra, 1942Indian Ocean raid, 1942Battle of Christmas Island, 1942Doolittle Raid, 1942air raids on Japan, 1942Japan Campaign, 1942Ogu Air Raid, 1942Japanese invasion of the Lesser Sunda Islands, 1942Japanese invasion of Zamboanga, 1942Battle of the Coral Sea, 1942Aleutian Islands Campaign, 1942Battle of Midway, 1942Battle of Dutch Harbor, 1942Attack on Sydney Harbour, 1942Shelling of Newcastle, 1942Bombardment of Fort Stevens, 1942Action of 5 July 1942, 1942Operation Fischreiher, 1942Attack on the Dureenbee, 1942Guadalcanal campaign, 1942Battle of Tulagi and Gavutu–Tanambogo, 1942Makin Island raid, 1942Battle of the Tenaru, 1942Battle of the Eastern Solomons, 1942Battle of Milne Bay, 1942Battle of Isurava, 1942Battle of Mission Ridge – Brigade Hill, 1942Battle of Edson's Ridge, 1942Actions along the Matanikau, 1942Lookout Air Raids, 1942Battle of Cape Esperance, 1942Battle of Goodenough Island, 1942Battle for Henderson Field, 1942Battle of the Santa Cruz Islands, 1942Koli Point action, 1942Matanikau Offensive, 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1945Bombing of Odawara, 1945Bombing of Isesaki, 1945Seishin Operation, 1945Philippines campaign of 1944–1945, 1945Operation Jurist, 1945Operation Tiderace, 1945Operation Agas, 1945UN Offensive Campaign, 195019401950Battle of Sio, 1943
415 placed engagements of the Pacific War in time order; taller ticks are more widely documented. Each tick is a link.

Record

Date5 December 1943
to 1 March 1944
PlaceSio, Papua New Guinea
5.955S, 147.370E
KindBattle, interwar and Second World War
Strength~15,000~8,000
Casualties and losses83 killed; 186 wounded1,421 killed; 2,198 found dead; 76 captured
Commanders
Battle of SioBattle of SioBattle of John's Knoll–Trevor's RidgeBattle of WareoBattle of SattelbergBattle of Scarlet BeachLanding at NadzabBattle of John's Knoll–Trevor's RidgeBattle of WareoBattle of SattelbergLanding at NadzabLaeMadang100 km5.955S, 147.370E
The recorded site, with the nearest other engagements in the atlas. Present-day coastlines, rivers and borders; towns from Natural Earth.

Nearest engagements

In the same war

Elsewhere in 1943

Battle of Sio is one of 4,429 engagements of the 20th century in the atlas and one of 70 in present-day Papua New Guinea.

Sources

Identity, coordinates, dates and the war from Wikidata Q4872384, released under CC0. Result, belligerents, commanders, strength and casualties from the infobox of the English Wikipedia article Battle of Sio, revision 1370589428, read 2026-11-14, licensed CC BY-SA 4.0; the article's text is not reproduced here. Present-day country and state from Natural Earth. Dates before 1582 follow the Julian calendar as recorded.