Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 20:05 and arrives at Koh Samui Samui International Airport at 21:35.
The flighttime is about 1h 30m. The distance travelled ("as the bird flies"): 113 Km. So the average speed is roughly 75 Km.
The best day to arrive at Bangkok is Wednesday and it would be best to avoid Monday, as prices are on average 293.47% higher than on Wednesday. (Average prices, based on 5455692 datapoints.)
We have a lot more statistics for flights TG 5966 and between Bangkok and Koh Samui.
