Flight Narita International Airport departs from Tokyo Narita International Airport at 21:55 and arrives at Hong Kong Hong Kong International Airport at 01:50.
The flighttime is about 4h 55m. The distance travelled ("as the bird flies"): 3064 Km. So the average speed is roughly 623 Km.
There is an 1 hour time difference between Tokyo and Hong Kong
The best day to arrive at Tokyo is Monday and it would be best to avoid Friday, as prices are on average 316.07% higher than on Monday. (Average prices, based on 16011757 datapoints.)
We have a lot more statistics for flights HX 631 and between Tokyo and Hong Kong.