Flight Incheon International Airport departs from Seoul Incheon International Airport at 07:05 and arrives at Tokyo Narita International Airport at 09:50.
The flighttime is about 2h 45m. The distance travelled ("as the bird flies"): 1555 Km. So the average speed is roughly 565 Km.
The best day to arrive at Seoul is Sunday and it would be best to avoid Friday, as prices are on average 334.19% higher than on Sunday. (Average prices, based on 5633354 datapoints.)
We have a lot more statistics for flights ZE 605 and between Seoul and Tokyo.