Flight Samui International Airport departs from Koh Samui Samui International Airport at 09:20 and arrives at Bangkok Suvarnabhumi Airport at 10:35.
The flighttime is about 1h 15m. The distance travelled ("as the bird flies"): 113 Km. So the average speed is roughly 90 Km.
The best day to arrive at Koh Samui is Tuesday and it would be best to avoid Wednesday, as prices are on average 84.75% higher than on Tuesday. (Average prices, based on 1275037 datapoints.)
We have a lot more statistics for flights PG 122 and between Koh Samui and Bangkok.