Please be aware that Seoul has multiple airports and that these results are for all airports serving the city.
The best month to arrive at Seoul is November and the most expensive month to fly is October. (Average prices, based on 1795 datapoints.)
The best day to arrive at Seoul is Monday and it would be best to avoid Saturday, as prices are on average 24.17% higher than on Monday. (Average prices, based on 2840 datapoints.)
The cheapest airline flying to Seoul is Jeju Air. They are 76% cheaper than Cathay Pacific. (Average prices, based on 1906 datapoints.)
At Seoul the most flights depart around 09:00. (Hourly flights, based on 2447 datapoints.)
From Seoul it is on average the cheapest to fly to Kuala Lumpur and to Hong Kong. (Average prices, based on 320 datapoints.)
From Seoul most of the flights depart to Kuala Lumpur, second best connected from Seoul is Tokyo. (Daily flights, based on 282 datapoints.)