Sihanouk International Airport, located 20 kilometres (12 mi) east of Sihanoukville City in Sihanoukville Province, is Cambodia's third largest international airport. It is named, like the province itself, after King Norodom Sihanouk. The airport is also known as Kang Keng Airport. The IATA code KOS is derived from Sihanoukville's alternative name "Kampong Som".