Military airfield and post-war development

The airport began as a military airfield built by the Imperial Japanese Army during World War II. It was originally known as Jesselton Airfield, with Kota Kinabalu then being called Jesselton. The airfield suffered significant damage from Allied bombings towards the end of the war. After the war, the Department of Civil Aviation (DCA) of North Borneo, which later became part of Malaysia's Sabah state, took over the airport's operation and maintenance.

With the end of the war, Jesselton Airfield was rehabilitated for civilian use. The Department of Civil Aviation began overseeing its operations and maintenance. This marked the beginning of its transition from a military installation to a public airport, laying the foundation for future commercial air travel in the region.

Transition to civil aviation

Regular passenger services commenced in May 1949 with a weekly flight operated by Malayan Airways from Singapore, stopping at Kuching and Labuan. The route was extended to Sandakan in September 1949. By 1950, the airport became a stopover point for biweekly flights between Hong Kong and Labuan, via Manila and Sandakan, operated by Cathay Pacific.

As domestic air travel grew, Sabah Airways Limited (later known as Borneo Airways) started operations in 1953, connecting Kota Kinabalu to other towns in Sabah, including Sandakan, Kudat, Ranau, Keningau and Tawau. This expansion significantly boosted the airport's importance as a regional hub.

With increasing air traffic and the need to accommodate larger aircraft, the airport began significant infrastructure upgrades. By 1957, the airport's original grass strip runway was resurfaced with bitumen, and a new terminal was constructed. This marked the beginning of the airport's transformation into a modern facility capable of handling more frequent commercial flights.

The runway underwent further extensions in the following years. By 1959, the runway was lengthened to 1,593 meters, allowing the operation of turboprop aircraft like the Malayan Airways turboprop Viscount aircraft. In 1963, the runway was lengthened again to 1,921 meters to accommodate the Comet 4 operated by Malaysian Airways.

As passenger traffic grew, the need for a larger terminal became apparent. In 1967, Cathay Pacific began operating a twice-weekly Convair 880 jet service to Hong Kong with a stop in Manila.

Corporatisation and modernisation

In 1992, the Department of Civil Aviation of Sabah was corporatised, and Malaysia Airports Holdings Berhad took over the management of KKIA. A major expansion project for both terminals began in 2006, with Terminal 1 undergoing renovation and the runway extended to 3,780 meters, allowing the airport to accommodate larger aircraft like the Airbus A380.

A major renovation and expansion of Terminal 1 was approved in mid-2005 by the Malaysian federal government, with the project costing RM1.4 billion. The runway was extended from 2,988 m (9,803 ft) to 3,780 m (12,402 ft), and the size of Terminal 1 was increased 34,000 m2 (370,000 sq ft) to 87,000 m2 (940,000 sq ft). The airport's air traffic control tower was relocated to a new standalone structure. The expanded Terminal 1 can accommodate four Boeing 747s, one Airbus A330, seven Boeing 737s, three Fokker 50s and three Dorniers at any given time. It has 12 jetways for passenger use.

The expansion allowed KKIA to handle the world's largest passenger aircraft, the Airbus A380. As a result, the airport's capacity increased to 12 million passengers annually—9 million for Terminal 1 and 3 million for Terminal 2.

Terminal 2, originally known as "Airport Lama," was the first terminal at Kota Kinabalu International Airport. After most operations moved to the new terminal in the 1980s, it remained inactive until 2006, when it was renovated to accommodate Low-cost carriers. The renovation was completed ahead of schedule, and the terminal reopened on 1 January 2007, in conjunction with Visit Malaysia Year 2007.

Due to congestion and limited space, all operations were eventually consolidated into Terminal 1, leading to Terminal 2's closure on 1 December 2015. The terminal is now used for cargo, charter flights, and general aviation.

Future developments

In July 2023, Malaysia Airports Sdn Bhd (MASB) announced a RM8.4 million allocation for a facelift program. The project includes refurbishing public toilets, resurfacing the runway, upgrading commercial lots and modernising the public address (PA) system to improve passenger comfort and operational efficiency.

In October 2023, Transport Minister Anthony Loke revealed long-term expansion plans aimed at increasing the airport's capacity from 9 million to 15.4 million passengers annually. As part of these efforts, the Transport Ministry is exploring the acquisition of adjacent land to facilitate the expansion under the 12th Malaysia Plan. The development is currently in the master planning phase, with consultations involving architecture and development firms.