Flight Incheon International Airport departs from Seoul Incheon International Airport at 15:45 and arrives at Tokyo Narita International Airport at 18:15.
The flighttime is about 2h 30m. The distance travelled ("as the bird flies"): 1555 Km. So the average speed is roughly 622 Km.
The best month to arrive at Seoul is August and the most expensive month to fly is May. (Average prices, based on 1460 datapoints.)
The best day to arrive at Seoul is Monday and it would be best to avoid Saturday, as prices are on average 32.71% higher than on Monday. (Average prices, based on 5623172 datapoints.)
We have a lot more statistics for flights GA 106 and between Seoul and Tokyo.