Flight Haneda Airport departs from Tokyo Haneda Airport at 12:30 and arrives at Seoul Incheon International Airport at 14:50.
The flighttime is about 2h 20m. The distance travelled ("as the bird flies"): 1487 Km. So the average speed is roughly 637 Km.
The best day to arrive at Tokyo is Wednesday and it would be best to avoid Sunday, as prices are on average 130.74% higher than on Wednesday. (Average prices, based on 1279631 datapoints.)
We have a lot more statistics for flights KE 2102 and between Tokyo and Seoul.
INR