Flight Soekarno–Hatta International Airport departs from Jakarta Soekarno–Hatta International Airport at 11:55 and arrives at Surabaya Juanda International Airport at 13:35.
The flighttime is about 1h 40m. The distance travelled ("as the bird flies"): 682 Km. So the average speed is roughly 409 Km.
The best month to arrive at Jakarta is August and the most expensive month to fly is December. (Average prices, based on 1179 datapoints.)
We have a lot more statistics for flights SQ 312 and between Jakarta and Surabaya.
