Flight Kansai International Airport departs from Osaka Kansai International Airport at 17:30 and arrives at Seoul Incheon International Airport at 19:20.
The flighttime is about 1h 50m. The distance travelled ("as the bird flies"): 1002 Km. So the average speed is roughly 547 Km.
The best day to arrive at Osaka is Tuesday and it would be best to avoid Sunday, as prices are on average 1642.26% higher than on Tuesday. (Average prices, based on 6324112 datapoints.)
We have a lot more statistics for flights LJ 238 and between Osaka and Seoul.