The Australian government ordered 24 F-111C aircraft to replace the RAAF's English Electric Canberras in the bombing and tactical strike role. The first F-111C was accepted at Nellis Air Force Base on 15 March 1973 with the RAAF's first six F-111Cs arriving at Amberley on 1 July 1973. In 1995 a further 15 F-111's were ordered to reduce the number of hours flown on the F-111C airframes, The F-111Gs were built as General Dynamics FB-111A strategic bombers, serving with USAF Strategic Air Command (SAC) ,these airframes had substantially lower accumulated airframe fatigue than the RAAF F-111c counterparts.
Compared to the basic F-111C airframe, the F-111G carries an additional 585 USG of JP-4 fuel which is about 3,500 lb or 11% more than the basic capacity. The fuselage and wing tank capacity is identical, at 4990 USG or about 32,400 lb. The engines deliver almost 20% higher thrust in service.
The last F-111s were retired on 3 December 2010, After 37 Years of Service.
In Australia, the F-111 was affectionately known as the "Pig"