The airport was opened on 4 April 1964. In 1974, the runway was extended to 2,400 metres. Due to increased traffic at the airport, a new terminal was built in 1980. In 1997, the terminal building was renovated and expanded. In December 2015, the privatisation of Kos Island International Airport and 13 other regional airports of Greece was finalised with the signing of the agreement between the Fraport AG/Copelouzos Group joint venture and the state privatisation fund. "We signed the deal today," the head of Greece's privatisation agency HRADF, Stergios Pitsiorlas, told Reuters. According to the agreement, the joint venture will operate the 14 airports (including Kos Island International Airport) for 40 years as of 11 April 2017. On 22 March 2017, Fraport AG and its Greek subsidiary Fraport Greece presented its plans for 14 regional airports that they had been handed control of by the Greek Government. The immediate actions by Fraport were to improve lighting, improve the marking of airside areas, upgrade sanitary facilities, enhance WiFi services and implementing better fire safety throughout the airport. The long-term plans by the operator, which initially were to continue until 2021, included the building of a new terminal and a new fire station, and the refurbishment of the waste water treatment plant. The new terminal provides significantly more check-in desks and security check lanes.