Flight Kansai International Airport departs from Osaka Kansai International Airport at 20:20 and arrives at Seoul Incheon International Airport at 22:25.
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 Wednesday and it would be best to avoid Sunday, as prices are on average 132.33% higher than on Wednesday. (Average prices, based on 6312086 datapoints.)
We have a lot more statistics for flights OZ 1155 and between Osaka and Seoul.