Please be aware that Seoul and Kuala Lumpur has multiple airports and that these results are for all airports serving the city.
The best month to fly between Seoul and Kuala Lumpur is June and the most expensive month to fly is January. (Average prices, based on 1204 datapoints.)
The cheapest airline flying from Seoul to Kuala Lumpur is AirAsia X. They are 62% cheaper than Korean Air. (Average prices, based on 1211 datapoints.)
The best time to fly is at around 20. (Average prices, based on 1302 datapoints.)