The Coastwatchers, also known as the Coast Watch Organisation, Combined Field Intelligence Service or Section C, Allied Intelligence Bureau, were Allied military intelligence operatives stationed on remote Pacific islands during World War II to observe enemy movements and rescue stranded Allied personnel. They played a significant role in the Pacific Ocean theatre and South West Pacific theatre, particularly as an early warning network during the Guadalcanal campaign.
Captain Chapman James Clare, district naval officer of Western Australia, proposed a coastwatching programme in 1919. In 1922, the Australian Commonwealth Naval Board directed the Naval Intelligence Division of the Royal Australian Navy to organise a coastwatching service. Walter Brooksbank, a civil assistant to the Director of Naval Intelligence, worked in the 1920s and 1930s to organise a skeleton service of plantation owners and managers whose properties were in strategic locations in northern Australia, the Australian controlled Territory of Papua and the British Solomon Islands. In 1939, when war appeared imminent, he expanded the coast-watching service with additional island planters, traders, miners and missionaries. During the war the civilian coastwatchers were augmented with about 400 coastwatchers who were Australian military officers, New Zealand servicemen, Pacific Islanders, or escaped Allied prisoners of war.
Lieutenant Commander Eric Feldt, based in Townsville, Queensland, led the Australian coastwatching organisation during much of World War II. Coastwatchers became particularly important in monitoring Japanese activity in the roughly one thousand islands that make up the Solomon Islands. Commander Feldt resigned his command due to illness in March 1943. His role was taken over by James McManus of the Royal Australian Navy.
The Australian military commissioned many personnel who took part in coastwatcher operations behind enemy lines as officers of the Royal Australian Navy Volunteer Reserve (RANVR) to protect them in case of capture, although the Imperial Japanese Army did not always recognise this status, and executed several such officers.