Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 11:20 and arrives at Seoul Incheon International Airport at 05:45.The flight has a short stop at Guangzhou.
The flighttime is about 16h 25m. The distance travelled ("as the bird flies"): 2992 Km. So the average speed is roughly 182 Km.
There is an 2 hour time difference between Bangkok and Seoul