Flight Incheon International Airport departs from Seoul Incheon International Airport at 16:15 and arrives at Hong Kong Hong Kong International Airport at 19:00.
The flighttime is about 3h 45m. The distance travelled ("as the bird flies"): 1621 Km. So the average speed is roughly 432 Km.
There is an 1 hour time difference between Seoul and Hong Kong
The best day to arrive at Seoul is Sunday and it would be best to avoid Wednesday, as prices are on average 69.88% higher than on Sunday. (Average prices, based on 18525122 datapoints.)
We have a lot more statistics for flights UO 631 and between Seoul and Hong Kong.