The world’s most popular flight route carries over 14 million passengers every year, with over one hundred take-offs per day. When asked to name the busiest flight route in the world, London to New York or Beijing to Shanghai might be among the options given.

Even Jeddah to Riyadh or Mumbai to Delhi could be great picks, each carrying millions of passengers every year. However, a little-known route in South Korea tops the list with over 40,000 airplane passengers making the trip every single day.

The route between Jeju International Airport in Jeju Island, with the capital, Seoul Gimpo Airport, has almost fallen into travel folklore. The journey has become extremely popular with Korean holidaymakers, and a trip has become almost a rite of passage.

Seven carriers operate on the route, with a whopping 130+ daily departures at times. Sounds like overkill? Not if companies can sustain demand. So why is the journey so popular? What sits on the other side of the airport terminal when passengers disembark?

Jeju Island is a major tourist site, a volcanic Island 80 km from the southern tip of the Korean Peninsula. The island is a natural paradise, with a strong culture, amazing food and great food, and a spate of tourist attractions such as the Hallasan volcano and Cheonjiyeon Falls.

The island had become a renowned UNESCO destination, listed as a World Natural Heritage site in 2007, which has only strengthened its appeal.

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Korea is six hours from Thailand, three from China and two from Japan, making Jeju Island and nearby Busan practical holiday destinations for residents not wanting to travel far to get a taste of something different. Who wouldn’t want to visit a sub-tropical island an hour’s flight from the capital?

The Jeju to Seoul acts as essentially a high-frequency air metro route with flights typically taking under an hour. Fares are usually low, with reports that passengers could secure tickets just before Christmas Day for just £14.

Passenger numbers climbed 1% in 2025, with annual ticket sales passing the 14.4million mark. However, there is still considerable room for growth, with the route operating 17% less than capacity levels seen back in 2019.