Flight Kansai International Airport departs from Osaka Kansai International Airport at 18:00 and arrives at Seoul Incheon International Airport at 20:05.
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 Monday and it would be best to avoid Saturday, as prices are on average 181.22% higher than on Monday. (Average prices, based on 5021426 datapoints.)
We have a lot more statistics for flights MM 709 and between Osaka and Seoul.