U.S. Air Force
The first of six initial production F-111s was delivered on 17 July 1967 to fighter squadrons at Nellis Air Force Base. These aircraft were used for crew training. 428th Tactical Fighter Squadron achieved initial operational capability on 28 April 1968.
After early testing, a detachment of six aircraft were sent in March 1968 to Southeast Asia for Combat Lancer testing in real combat conditions in Vietnam. In little over a month, three aircraft were lost and the combat tests were halted. It turned out that all three had been lost through a malfunction in the horizontal stabilizer, not by enemy action. This caused a storm of criticism in the U.S. It was not until 1971 that 474 TFW was fully operational.
September 1972 saw the F-111 back in Southeast Asia, stationed at Takhli Air Base, Thailand. F-111As from Nellis AFB participated in the final month of Operation Linebacker and later the Operation Linebacker II aerial offensive against the North Vietnamese. F-111 missions did not require tankers or ECM support, and they could operate in weather that grounded most other aircraft. One F-111 could carry the bomb load of four McDonnell Douglas F-4 Phantom IIs. The worth of the new aircraft was beginning to show; F-111s flew more than 4,000 combat missions in Vietnam with only six combat losses.
From 30 July 1973 F-111As of the 347th Tactical Fighter Wing (347th TFW) were stationed at Takhli Air Base. The 347th TFW conducted bombing missions in Cambodia in support of Khmer Republic forces until 15 August 1973 when US combat support ceased in accordance with the Case–Church Amendment. The 347th TFW was stationed at Korat Royal Thai Air Force Base from 12 July 1974 until 30 June 1975. In May 1975 347th TFW F-111s provided air support during the Mayaguez incident.
On 14 April 1986, 18 F-111s and approximately 25 Navy aircraft conducted air strikes against Libya under Operation El Dorado Canyon. The 18 F-111s of the 48th Tactical Fighter Wing and the 20th Tactical Fighter Wing flew what turned out to be the longest fighter combat mission in history. The round-trip flight between RAF Lakenheath/RAF Upper Heyford, United Kingdom and Libya of 6,400 miles (10,300 km) spanned 13 hours. One F-111 was lost over Libya, probably shot down.
F-111s participated in the Gulf War (Operation Desert Storm) in 1991. During Desert Storm, F-111Fs completed 3.2 successful strike missions for every unsuccessful one, better than any other U.S. strike aircraft used in the operation. The group of 66 F-111Fs dropped almost 80% of the war's laser-guided bombs, including the GBU-15 and the penetrating, bunker-buster GBU-28. Eighteen F-111Es were also deployed during the operation. The F-111s were credited with destroying more than 1,500 Iraqi tanks and armored vehicles. Their use in the anti-armor role was dubbed "tank plinking".
The F-111 was in service with the USAF from 1967 through 1998. The Strategic Air Command had FB-111s in service from 1969 through 1992. At a ceremony marking the F-111's USAF retirement, on 27 July 1996, it was officially named Aardvark, its long-standing unofficial name. The USAF retired the EF-111 electronic warfare variant in 1998.
Royal Australian Air Force
The Australian government ordered 24 F-111C aircraft to replace the RAAF's English Electric Canberras in the bombing and tactical strike role. While the first aircraft was officially handed over in September 1968, structural issues delayed the entry into service. The first F-111C was accepted at Nellis Air Force Base on 15 March 1973. The RAAF's first six F-111Cs arrived at Amberley on 1 July 1973, and three subsequent flights of six F-111s arrived on 27 July, 28 September and 4 December. F-111Cs were allocated to No. 1 Squadron and No. 6 Squadron, under the control of No. 82 Wing.
The purchase proved to be highly successful for the RAAF. Although it never saw combat, the F-111C was the fastest, longest range combat aircraft in Southeast Asia. Aviation historian Alan Stephens has written that they were "the preeminent weapons system in the Asia-Pacific region" throughout their service and provided Australia with "a genuine, independent strike capability". Former Indonesian defense minister Benny Murdani told his Australian counterpart Kim Beazley that when others became upset with Australia during Indonesian cabinet meetings, Murdani told them "Do you realise the Australians have a bomber that can put a bomb through that window on to the table here in front of us?"
The drawdown of the RAAF's F-111 fleet began with the retirement of the F-111G models operated by No. 6 Squadron in late 2007. One of the reasons given for the F-111s' retirement was the high maintenance time required for every flight hour. The last F-111s were retired on 3 December 2010.