Flight Kansai International Airport departs from Osaka Kansai International Airport at 15:25 and arrives at Seoul Incheon International Airport at 17:20.
The flighttime is about 1h 55m. The distance travelled ("as the bird flies"): 1002 Km. So the average speed is roughly 523 Km.
The best day to arrive at Osaka is Saturday and it would be best to avoid Friday, as prices are on average 243.87% higher than on Saturday. (Average prices, based on 5038004 datapoints.)
We have a lot more statistics for flights TW 284 and between Osaka and Seoul.