The 31st wing arrived at Tuy Hoa, and was assigned to the 7th Air Force, on Christmas Day 1966. The wing provided close air support and air interdiction for US and Army of the Republic of Vietnam (ARVN) units in the central region of the country. In 1968 they helped defend installations against enemy forces during the Tet Offensive and the siege of Khe Sanh and were later singled out for their outstanding contribution during the extraction of friendly forces from Kham Duc. They reached the 100,000 combat sortie milestone in September 1969. The wing earned two Outstanding Unit Awards, one with a combat "V" device, a Presidential Unit Citation, two Republic of Vietnam Gallantry Crosses with Palm and ten campaign streamers for action in Vietnam. On 15 October 1970, the wing returned to Homestead without people or equipment as part of the United States force reduction in Vietnam. At the same time, the wing switched from flying North American F-100 Super Sabres to McDonnell Douglas F-4E Phantom IIs.