Flight Incheon International Airport departs from Seoul Incheon International Airport at 15:05 and arrives at Jakarta Soekarno–Hatta International Airport at 20:05.
The flighttime is about 7h 00m. The distance travelled ("as the bird flies"): 2960 Km. So the average speed is roughly 423 Km.
There is an 2 hour time difference between Seoul and Jakarta
The best month to arrive at Seoul is August and the most expensive month to fly is July. (Average prices, based on 955 datapoints.)
We have a lot more statistics for flights SQ 627 and between Seoul and Jakarta.