Please be aware that Seoul has multiple airports and that these results are for all airports serving the city.
The best month to fly between Seoul and Singapore is March and the most expensive month to fly is December. (Average prices, based on 679 datapoints.)
The best day to arrive at Seoul is Tuesday and it would be best to avoid Sunday, as prices are on average 32.48% higher than on Tuesday. (Average prices, based on 679 datapoints.)
The cheapest airline flying from Seoul to Singapore is Asiana Airlines. They are 30% cheaper than Singapore Airlines. (Average prices, based on 686 datapoints.)
The best time to fly is at around 11. (Average prices, based on 782 datapoints.)