Please be aware that Tokyo has multiple airports and that these results are for all airports serving the city.
The best month to fly between Tokyo and Singapore is March and the most expensive month to fly is January. (Average prices, based on 329 datapoints.)
The best day to arrive at Tokyo is Monday and it would be best to avoid Wednesday, as prices are on average 99.33% higher than on Monday. (Average prices, based on 329 datapoints.)
The cheapest airline flying from Tokyo to Singapore is Scoot-Tiger. They are 80% cheaper than All Nippon Airways. (Average prices, based on 342 datapoints.)