Please be aware that Kuala Lumpur and Seoul has multiple airports and that these results are for all airports serving the city.
The best month to fly between Kuala Lumpur and Seoul is July and the most expensive month to fly is August. (Average prices, based on 4893 datapoints.)
The best day to arrive at Kuala Lumpur is Monday and it would be best to avoid Friday, as prices are on average 16.9% higher than on Monday. (Average prices, based on 4841 datapoints.)