Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 10:20 and arrives at Koh Samui Samui International Airport at 11:30.
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 Monday and it would be best to avoid Saturday, as prices are on average 158.82% higher than on Monday. (Average prices, based on 5038849 datapoints.)
We have a lot more statistics for flights PG 131 and between Bangkok and Koh Samui.