Flight Kansai International Airport departs from Osaka Kansai International Airport at 12:20 and arrives at Seoul Incheon International Airport at 14:25.
The flighttime is about 2h 05m. The distance travelled ("as the bird flies"): 1002 Km. So the average speed is roughly 481 Km.
The best day to arrive at Osaka is Saturday and it would be best to avoid Wednesday, as prices are on average 869.47% higher than on Saturday. (Average prices, based on 5177853 datapoints.)
We have a lot more statistics for flights GA 724 and between Osaka and Seoul.