Flight Incheon International Airport departs from Seoul Incheon International Airport at 10:25 and arrives at Tokyo Narita International Airport at 12:55.
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 day to arrive at Seoul is Monday and it would be best to avoid Friday, as prices are on average 130.29% higher than on Monday. (Average prices, based on 6959225 datapoints.)
We have a lot more statistics for flights 7C 1103 and between Seoul and Tokyo.