Incheon International Airport was named the best airport in the world for an unprecedented 12th year running in the 2016 Airport Service Quality Awards by the Airports Council International.
The award came despite a luggage glitch that held up traffic for several hours on one occasion and a security hole that allowed two Chinese passengers to sneak through the barriers.
Incheon International Airport Corporation (IIAC) on Tuesday said it scored 4.994 out of five points to rank first in the Asia-Pacific category and the category for airports handling 40 million passengers or more per year.
The ASQ survey rates airports based on customer satisfaction in 34 categories including friendliness, cleanliness, convenience, access, service, and facility management.
Incheon was 0.007 points ahead of the three airports who share second place -- Singapore's Changi International Airport, Indira Gandhi International Airport in Delhi, and Chhatrapati Shivaji International Airport in Mumbai.
"It seems we were able to hold on to the top opposition thanks to our efforts to improve services including new mobile check-in counters and more security screening areas," an IIAC spokesman said.
Gimpo International Airport came second in the category for mid-sized airports handling 15 million to 25 million passengers a year. It tied with Sanya Phoenix International Airport in China.
Gimpo had led the field for six years but relinquished the top spot to Haikou Meilan International Airport in China in 2016.