Flight Changi Airport departs from Singapore Changi Airport at 01:45 and arrives at Seoul Incheon International Airport at 08:55.
The flighttime is about 6h 10m. The distance travelled ("as the bird flies"): 2923 Km. So the average speed is roughly 474 Km.
There is an 1 hour time difference between Singapore and Seoul
The best day to arrive at Singapore is Wednesday and it would be best to avoid Sunday, as prices are on average 136.63% higher than on Wednesday. (Average prices, based on 920357 datapoints.)
We have a lot more statistics for flights OZ 754 and between Singapore and Seoul.
