Flight Incheon International Airport departs from Seoul Incheon International Airport at 14:50 and arrives at Tokyo Narita International Airport at 17:15.
The flighttime is about 2h 25m. The distance travelled ("as the bird flies"): 1555 Km. So the average speed is roughly 643 Km.
The best day to arrive at Seoul is Tuesday and it would be best to avoid Sunday, as prices are on average 128.49% higher than on Tuesday. (Average prices, based on 6733955 datapoints.)
We have a lot more statistics for flights 7C 1107 and between Seoul and Tokyo.