Competition has intensified among local low-budget carriers for the world’s busiest domestic air route, Seoul to Jejudo Island, which has become a top destination for tourists from China and Southeast Asia.

In the country’s competitive aviation market, local air carriers are eyeing the lucrative route as Jejudo Island’s tourism industry has grown rapidly in recent years.

According to data from the International Air Transport Association, over 13.8 million passengers flew from Gimpo-Jeju last year, making it the world’s busiest domestic air route.

Another study from the Ministry of Land, Infrastructure, and Transport forecasts that Jeju International Airport will become overcrowded by 2018.

“The Gimpo-Jeju route is the cream of the crop, with an occupancy rate that exceeds 80 percent every month. There’s no difference between peak season and off-peak season for Jejudo Island,” a Jin Air official said.

Starting Monday, Jin Air launched flights from Gimpo-Jeju with B777-200ER wide-body planes.

This is first time for the country’s low-budget carrier to service a domestic destination with a long-haul wide-body airliner which can carry 355 people, while the B737-800, which was previously used for the route, can seat 183 passengers. The airline’s B777-200ER service will make eight flights a day.

Korea’s largest low-cost airline, Jeju Air, which uses Jejudo Island as its main hub, is also considering increasing its number of flights to the southern resort island.

Thanks to the growing number of Chinese tourists who visit Jejudo Island via Gimpo from major Chinese cities including Beijing, Shanghai and Hangzhou, budget carriers are not the only ones competing for the flight path, dubbed “the golden route.” Larger airlines, such as nation’s No. 2 air carrier Asiana Airlines, are also looking at increasing their number of flights.

Asiana Airlines, which carried the largest number of passengers on the route last year, increased its number of flights from Seoul to Jeju by 22.7 percent to 19,066 flights in 2014.

An airline spokesperson said that Asiana planned to boost its number of flights.

“The Gimpo-Jeju flight path is a large, uncompromising market for Korean air carriers which should grab the momentum of China’s fast-growing tourism industry,” the official said.

By Park Han-na (hnpark@heraldcorp.com)