| Papuan Infantry Battalion | |
|---|---|
 Sergeant Bengari of A Company, PIB on 5 August 1944 | |
| Active | 1940–1946 |
| Country | Australia |
| Branch | Australian Army |
| Type | Infantry |
| Role | Reconnaissance |
| Size | One battalion ~300–700 men |
| Part of | 8th Military District New Guinea Force |
| Garrison/HQ | Port Moresby |
| Nickname(s) | "Green Shadows" |
| Colours | Red and green |
| Engagements | Second World War |
| Battle honours | South West Pacific 1942–45, Kokoda Trail, Kokoda-Deniki, Nassau Bay, Tambu Bay, Finschhafen, Scarlet Beach, Liberation of Australian New Guinea, Sio-Sepik River, Kaboibus-Kiarivu and Bonis-Porton |
| Commanders | |
| Notable commanders | William Watson |
| Insignia | |
| Unit colour patch |  |
The Papuan Infantry Battalion (PIB) was a unit of the Australian Army raised in the Territory of Papua for service during the Second World War. Formed in early 1940 in Port Moresby to help defend the territory in the event of a Japanese invasion, its soldiers were primarily Papuan natives led by Australian officers and non-commissioned officers. Following the outbreak of the Pacific War, the PIB served in many of the Allied campaigns in New Guinea; however, due to the nature of its role its sub-units mainly operated separately, attached to larger Australian and US Army units and formations. Slow in forming, the first members of the PIB were not officially posted in until March 1941. By 1942 it consisted of only three companies, all of which were under-strength and poorly equipped. It was subsequently employed on scouting, reconnaissance and surveillance patrols against the Japanese, where the natural bushcraft of its native soldiers could be used to their advantage. The PIB was sent forward in June 1942 to patrol the northern coast of Papua and was dispersed over a wide area. These small parties were the first to make contact with the Imperial Japanese forces upon their landing in Papua, before participating in the Kokoda Track campaign. As part of Maroubra Force, the PIB fought alongside the Australian 39th Battalion at Kokoda, Deniki, and Isurava as the Japanese forced them back along the Kokoda track, but was withdrawn before the campaign finally turned in favour of the Australians.
Following the recapture of the northern beachheads of Buna, Gona and Sanananda, the Allies moved onto the offensive in New Guinea. The PIB took part in the advance to Salamaua in 1943, before fighting along the Markham, Ramu, and Sepik rivers during the Ramu Valley – Finisterre Range campaign, and on the Huon peninsula, assisting in the capture of Finschhafen and Sattelberg, and pursuing the Japanese as they retreated along the northern coastline towards Saidor in 1943–1944. The battalion was temporarily withdrawn from operations to reorganise in 1944, and together with several New Guinea Infantry Battalions (NGIBs) that were subsequently raised by the Australian Army, the PIB was formed into the Pacific Islands Regiment (PIR) in November 1944. In 1945, it was deployed to Bougainville where the battalion's companies were spread across the fronts from Bonis to Buin during the final months of the war. Such was their effectiveness that the Japanese referred to the PIB as "Green Shadows" due to their ability to fade into and appear from the jungle unexpectedly, with its soldiers becoming noted for their ferocity and tenacity. After the end of the war the battalion was used to guard Japanese prisoners of war, before being disbanded in August 1946. In 1951, the PIR was reformed, drawing its lineage from the PIB and NGIBs.