Flight Changi Airport departs from Singapore Changi Airport at 09:25 and arrives at Tokyo Narita International Airport at 17:30.
The flighttime is about 7h 05m. The distance travelled ("as the bird flies"): 4385 Km. So the average speed is roughly 619 Km.
There is an 1 hour time difference between Singapore and Tokyo
The best day to arrive at Singapore is Monday and it would be best to avoid Wednesday, as prices are on average 65.27% higher than on Monday. (Average prices, based on 493042 datapoints.)
We have a lot more statistics for flights SQ 12 and between Singapore and Tokyo.