Flight Incheon International Airport departs from Seoul Incheon International Airport at 14:35 and arrives at Hong Kong Hong Kong International Airport at 17:20.
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 Friday and it would be best to avoid Sunday, as prices are on average 95.62% higher than on Friday. (Average prices, based on 17928988 datapoints.)
We have a lot more statistics for flights UO 631 and between Seoul and Hong Kong.