Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 15:50 and arrives at Koh Samui Samui International Airport at 17:00.
The flighttime is about 1h 10m. The distance travelled ("as the bird flies"): 113 Km. So the average speed is roughly 97 Km.
The best day to arrive at Bangkok is Tuesday and it would be best to avoid Monday, as prices are on average 82.63% higher than on Tuesday. (Average prices, based on 5037291 datapoints.)
We have a lot more statistics for flights PG 163 and between Bangkok and Koh Samui.
