People using the 88,443 square-meter terminal can now benefit from a shorter baggage processing time of about five minutes from the previous 15 minutes. There are now 14 security checkpoints compared to 10 in the past, which can result in shorter preflight screening lines.

"We will do our utmost to provide the optimal service to meet steadily growing demand for domestic flights and the public's rising expectations for aviation services," Kim Myung-woon, acting CEO of the Korea Airports Corp., said.

An average of 68,500 passengers used Gimpo International Airport per day last year, according to the airport operator.

The airport in southwestern Seoul had served as South Korea's main gateway for decades until 2001, when Incheon International Airport opened and took over most of the international passenger traffic.

Gimpo has since catered to international travelers by operating five routes to Japan, China and Taiwan. (Yonhap)