A Seoul-Colombo return ticket is priced at around 90,000 rupees.
The airline quit the country in 1984.
Sri Lanka is now seeing a resurgence of tourism after a 30 year war ended in May 2009.
Korean Air will come to Colombo Sundays, Tuesdays and Thursdays and continue on to Male in the Maldives.
Priyantha Mendis, managing director of Alpha Tours, Korean Air's General Sales Agent in Sri Lanka said Korea has a large outbound travel market and the equivalent of 25 percent of their population travelled abroad.
Korea has become even more prosperous after the East Asian crisis, as the country's central bank moved to a near-orthodox floating exchange rate regime, allowing the country to have a strong currency and low inflation.
Mendis said many were flying to Maldives especially for honeymooning, and Sri Lanka was hoping to attract a part of that traffic.
Harsha De Saram head of Alpha group's hotel division said they hoped to attract Korean travellers to their niche properties.