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 1239 datapoints.)
The best day to arrive at Seoul is Wednesday and it would be best to avoid Saturday, as prices are on average 25.12% higher than on Wednesday. (Average prices, based on 1871 datapoints.)
The cheapest airline flying to Seoul is Air Busan. They are 51% cheaper than China Southern Airlines. (Average prices, based on 1424 datapoints.)
At Seoul the most flights depart around 09:00. (Hourly flights, based on 1914 datapoints.)
From Seoul it is on average the cheapest to fly to Busan and to Jeju City. (Average prices, based on 479 datapoints.)
From Seoul most of the flights depart to Tokyo, second best connected from Seoul is Jeju City. (Daily flights, based on 278 datapoints.)