Flight Haneda Airport departs from Tokyo Haneda Airport at 08:55 and arrives at Singapore Changi Airport at 14:55.
The flighttime is about 7h 00m. The distance travelled ("as the bird flies"): 4314 Km. So the average speed is roughly 616 Km.
There is an 1 hour time difference between Tokyo and Singapore
The best day to arrive at Tokyo is Sunday and it would be best to avoid Saturday, as prices are on average 231.96% higher than on Sunday. (Average prices, based on 647452 datapoints.)
We have a lot more statistics for flights SQ 631 and between Tokyo and Singapore.
