Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 10:10 and arrives at Koh Samui Samui International Airport at 11:40.
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 Sunday and it would be best to avoid Thursday, as prices are on average 152.77% higher than on Sunday. (Average prices, based on 4833753 datapoints.)
We have a lot more statistics for flights PG 127 and between Bangkok and Koh Samui.