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 World War II, which ran from 1939 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 ofWorld War II1939 to 1945

Where it sits in World War II

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313 placed engagements of World War II 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 2,997 engagements of the 20th century in the atlas and one of 54 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.