Korean Air's low-cost subsidiary Jin Air has started its first international service to Bangkok.
Daily flights between Seoul-Incheon and Bangkok began on 21 December, says an airline spokesman.
The service is operated on Boeing 737-800 aircraft.
Jin plans to start services to cities in Japan and China, and is studying these markets, adds the spokesman.
The carrier operates a fleet of four 737-800s and is considering getting a fifth in March 2010, says the spokesman.