Flight Changi Airport departs from Singapore Changi Airport at 09:20 and arrives at Tokyo Narita International Airport at 17:05.
The flighttime is about 6h 45m. The distance travelled ("as the bird flies"): 4385 Km. So the average speed is roughly 650 Km.
There is an 1 hour time difference between Singapore and Tokyo
The best day to arrive at Singapore is Thursday and it would be best to avoid Wednesday, as prices are on average 75.03% higher than on Thursday. (Average prices, based on 706235 datapoints.)
We have a lot more statistics for flights SQ 12 and between Singapore and Tokyo.