The unit was initially equipped with Bristol Beauforts and Beaufighters, and later received Douglas Bostons and de Havilland Mosquitos, among other types.

It was reorganised as a fighter conversion unit flying P-51 Mustangs and CAC Wirraways in February 1946, and disbanded in July 1947.

5 OTU was re-raised at Williamtown in April 1970 as a jet fighter conversion unit, equipped with CAC Sabres, de Havilland Vampires, and Macchi MB-326s.

During World War II, the Royal Australian Air Force (RAAF) established several operational training units (OTUs) to convert recently graduated pilots from advanced trainers to combat aircraft, and to add fighting ability to the flying skills they had already learned.

[1] Employing as they did warplanes that were more advanced and more powerful than trainers, and teaching combat techniques that often carried high risk, OTUs generally suffered higher accident rates than other flying training schools.

5 OTU relocated to Tocumwal, New South Wales, on 20 October 1943, it had begun running courses on Douglas Bostons.

5 OTU arrived at Williamtown, New South Wales, on 1 May 1944 and accepted handover of the base from a small detachment of personnel formerly of No.

[4] Mosquito fighter ace Charles Scherf briefly served as chief flying instructor in late 1944.

[4] Ace Charles Crombie was the unit's chief flying instructor when he was killed in a Beaufighter crash at Williamtown on 26 August 1945.

5 OTU was reorganised as a crew conversion unit, CCU (Fighter), operating North American P-51 Mustangs and CAC Wirraways.

81 Wing, comprising three RAAF Mustang squadrons, as part of the British Commonwealth Occupation Force in Japan.

5 OTU was re-formed at Williamtown on 1 April 1970 to provide pilots with operational training prior to their conversion to the Dassault Mirage III fighter.

The unit's reactivation was celebrated with a dinner attended by its original commanding officer, Bruce Rose, and a flypast of forty-nine aircraft from No.

[4] Its aircraft also participated in joint exercises and display flights, including air shows celebrating the RAAF's 1971 golden jubilee.