Why Jeju To Seoul Is The World’s Busiest Route

The world’s busiest route in 2019 wasn’t a long-haul business route. It was a short, one hour and ten-minute hop between the capital of South Korea and the nearby island of Jeju. With more than 85,000 flights over the year from eight different airlines, here’s a look at why the route between Jeju and Seoul is the world’s busiest, and the challenges it presents for the future.

Jeju Air
The route between Jeju and Seoul had 40% more capacity than the next busiest route in 2019. Photo: Jeju Air

The Hawaii of South Korea

The face of the aviation marketplace has changed beyond all recognition in 2020. However, before the crisis hit, there was one airline route that stood out above all other for being the busiest route in the world. Surprisingly, it wasn’t London to New York, or even the popular Hong Kong to Taipei route. It wasn’t even an international route, but rather a domestic one, flying between Seoul in South Korea and the island of Jeju.

According to analysis by OAG, flights between Seoul (GMP) and Jeju (CJU) in 2019 deployed some 17 million seats over the year. That’s around 48,000 seats a day, and some 40% more capacity than the next busiest route (which was Sapporo to Tokyo, if you’re interested). While some of these are business trips or visiting family and friends traffic, the vast majority is tourism, with more than 15 million visitors arriving on the island each year.

Jeju Island
Jeju Island’s subtropical beauty has made it a popular holiday hotspot for visitors from South Korea and further afield. Photo: Douglas Knisely via Wikimedia

Over the past 10 years, Jeju has become a booming tourist hotspot for Koreans, and is sometimes dubbed the ‘Hawaii of South Korea’. However, the influx of visitors has come at a cost to the island, with reports of massive pollution problems, littering, and exhaustion of natural resources. Let’s take a look at this incredibly busy airline route.

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Who flies the route?

The trip between Jeju and Seoul is not particularly long. Clocking in at around 450 km, the flight takes just over an hour to complete, and yet it’s still incredibly competitive. Under normal circumstances, eight different carriers fly the route, with departures throughout the day at roughly 10-minute intervals.

OAG’s analysis shows that this route is the 10th most competitive domestic route in terms of the number of carriers. However, it soars above the competition in terms of frequency, with more than 85,000 flights taking to the skies in 2019.

T'Way Air Boeing
Smaller carriers are complemented by capacity from heavyweights Korean and Asiana. Photo: Getty Images

Providing capacity on the route are a number of smaller carriers: T’Way Air, Air Seoul, Jin Air, Jeju Air, Air Busan and Eastar Jet. However, also pitching in on the capacity are regional heavyweights Korean Air and Asiana. Aircraft types range from the Airbus and Boeing narrowbody lines to widebody A330 and 767s as well as the odd 777-200.

The future of the world’s busiest route

While the aviation industry in general has been thrown into turmoil in 2020, the world’s busiest route is performing surprisingly well. Given that this is a domestic route, it seems Korean’s are still willing to take a trip to their homegrown paradise, even during a pandemic.

FlightRadar24.com notes that there are still in excess of 850 flights a week scheduled on the route, and a glance at Google Flights shows a plethora of departures scheduled for the coming days. While some of the carriers are facing their own struggles, it seems this remains a lucrative route for deploying capacity while international travel remains low.

Why Jeju To Seoul Is The World’s Busiest Route
Even now, multiple flights a day service the route (this is just the schedule between 10:00 and 12:00) Image: Google Flights

However, the destination is facing issues that are unrelated to the pandemic. It’s not only South Korea that loves to visit Jeju. Visitors from China, Malaysia, Thailand and Japan further bloat the tourist arrivals, causing problems with traffic jams, rubbish-strewn beaches and depleted water supplies.

Why Jeju To Seoul Is The World’s Busiest Route
Traffic to destinations outside of South Korea is usually busy too. Image: FlightRadar24.com

The surge in popularity has caused issues for the airport too. In 1997, it handled just nine million passengers. Last year, it passed the 30 million milestones for the first time. The airport was only designed to handle a maximum of 26 million passengers, so is regularly overcrowded and struggling to manage.

Jeju Airport
Even now, the airport remains insanely crowded and busy. Photo: Getty Images

A second airport is planned for the island, at the southern city of Seogwipo, with investment of $3.8 billion earmarked for the development. It is expected to open in 2025, but has been a contentious project with the island residents who argue there are too many visitors already.

While COVID may have granted a reprieve to Jeju, with international visitor numbers dropping off a cliff, Seoul’s domestic route looks set to remain one of the world’s busiest routes in 2020.