U-Tapao began as a navy project. English Wikipedia’s article on the Naval Air Division says the Royal Thai Navy built an airfield at Ban U-Tapao in Rayong in 1957, and that the United States offered construction assistance in return for using part of it. What turned a coastal field into one of the most important airfields in Asia was the Vietnam War. Construction of the American base began on 15 October 1965 and was completed on 2 June 1966.

The first tenants were tankers. Wikipedia’s base article records the first KC-135s in August 1966 and 15 tankers by September, under the 4258th Strategic Wing; between 1966 and 1970 the wing’s tankers flew more than 50,000 sorties. A Thai–American agreement of 2 March 1967 allowed 15 B-52s, and the first arrived on 10 April 1967, flying their first missions the next day. From then until 1973 U-Tapao was the primary South-East Asian base for the B-52.

The B-52s at U-Tapao flew the Arc Light carpet-bombing missions over South Vietnam and, from March 1969, the secret Menu bombing of Cambodia, which continued until 26 May 1970. Wikipedia credits the wing with more than 35,000 strikes over South Vietnam from 1967 to 1970, and with 2,548 sorties in support of the siege of Khe Sanh in early 1968. Each B-52 carried an average of 108 bombs of 500 and 750 lb per mission. The 4258th was redesignated the 307th Strategic Wing on 21 January 1970, and by March 1972 51 B-52s were based here.

The climax was Linebacker II, the bombing of Hanoi and Haiphong that began on 18 December 1972. Wikipedia says 129 B-52s attacked in three waves, and that U-Tapao’s B-52Ds, able to carry more bombs, flew 729 sorties and dropped 13,640 tonnes in 11 days. The campaign cost the US Air Force 16 B-52s lost, nine more heavily damaged and 33 aircrew killed or missing, according to the same article; how many of those losses were U-Tapao aircraft is not broken down there. The wing ended combat operations on 14 August 1973.

U-Tapao’s last American operation was a rescue. On 12 May 1975 the Khmer Rouge seized the US container ship SS Mayaguez, and U-Tapao became the staging point for the Marine assault on Koh Tang island. Wikipedia records that a CH-53 crashed during the operation, killing 18 security policemen and its five-man crew, and that the operation cost 15 Americans killed in action and three missing.

Strategic Air Command units left in December 1975, the last rescue group on 31 January 1976, and the base was formally returned to Thailand on 13 June 1976. The Royal Thai Navy kept it.

Under Thai ownership U-Tapao became the home of the Naval Air Division’s First Air Wing, flying patrol, search and rescue and forward air control aircraft and, more recently, drones. Its long runway also made it useful as a civil airport: when protesters closed Bangkok’s airports in 2008, Wikipedia says, U-Tapao became Thailand’s supplementary international gateway for a time. A second terminal opened in February 2019, a six-phase expansion aiming at 60 million passengers a year was approved in 2022, and construction of the first phase, including a second runway, began in November 2025. Between October 2023 and September 2024 the airport handled 370,210 passengers and 5,788 aircraft movements.

The Americans have come back as guests. Wikipedia records a multinational headquarters for tsunami relief here after the Indian Ocean tsunami of December 2004, and 36 US C-130 relief flights to Myanmar after Cyclone Nargis in May 2008. It also reports that Thailand allowed American aircraft flying to Iraq and Afghanistan to use the base, and that retired intelligence officials have said detainees, including Abu Zubaydah, may have been interrogated here; the Thai government’s position on that claim was not found in the sources reached. In May 2026 Airbus named U-Tapao as the base for the navy’s two new C295s.