Please be aware that Seoul has multiple airports and that these results are only for Incheon International Airport.
The best month to arrive at Seoul is November and the most expensive month to fly is October. (Average prices, based on 3733 datapoints.)
The best day to arrive at Seoul is Tuesday and it would be best to avoid Friday, as prices are on average 61.6% higher than on Tuesday. (Average prices, based on 306 datapoints.)
The cheapest airline flying to Seoul is VietJet Air. They are 76% cheaper than Cathay Pacific. (Average prices, based on 3850 datapoints.)
At Seoul the most flights depart around 22:00. (Hourly flights, based on 4464 datapoints.)
From Seoul it is on average the cheapest to fly to Osaka and to Hong Kong. (Average prices, based on 382 datapoints.)
From Seoul most of the flights depart to Kuala Lumpur, second best connected from Seoul is Osaka. (Daily flights, based on 288 datapoints.)