Flight Narita International Airport departs from Tokyo Narita International Airport at 20:15 and arrives at Bangkok Don Mueang International Airport at 01:35.
The flighttime is about 7h 20m. The distance travelled ("as the bird flies"): 4524 Km. So the average speed is roughly 617 Km.
There is an 2 hour time difference between Tokyo and Bangkok
The best day to arrive at Tokyo is Saturday and it would be best to avoid Thursday, as prices are on average 309.55% higher than on Saturday. (Average prices, based on 103013 datapoints.)
We have a lot more statistics for flights XJ 607 and between Tokyo and Bangkok.