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 January. (Average prices, based on 1706 datapoints.)
The best day to arrive at Seoul is Wednesday and it would be best to avoid Saturday, as prices are on average 25.35% higher than on Wednesday. (Average prices, based on 2543 datapoints.)
The cheapest airline flying to Seoul is Philippines AirAsia. They are 27% cheaper than Shandong Airlines. (Average prices, based on 1941 datapoints.)
At Seoul the most flights depart around 23:00. (Hourly flights, based on 2347 datapoints.)
From Seoul it is on average the cheapest to fly to Shanghai and to Ho Chi Minh City. (Average prices, based on 580 datapoints.)
From Seoul most of the flights depart to Tokyo, second best connected from Seoul is Shanghai. (Daily flights, based on 192 datapoints.)