Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 15:20 and arrives at Riyadh King Khaled International Airport at 19:30.
The flighttime is about 8h 10m. The distance travelled ("as the bird flies"): 5991 Km. So the average speed is roughly 734 Km.
There is an 4 hour time difference between Bangkok and Riyadh
