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 February and the most expensive month to fly is May. (Average prices, based on 233 datapoints.)
The best day to arrive at Seoul is Wednesday and it would be best to avoid Sunday, as prices are on average 91.39% higher than on Wednesday. (Average prices, based on 211 datapoints.)
The cheapest airline flying from Seoul to Singapore is Scoot-Tiger. They are 56% cheaper than Korean Air. (Average prices, based on 242 datapoints.)
The best time to fly is at around 9. (Average prices, based on 376 datapoints.)