Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 16:00 and arrives at Koh Samui Samui International Airport at 17:05.
The flighttime is about 1h 05m. The distance travelled ("as the bird flies"): 113 Km. So the average speed is roughly 104 Km.
The best day to arrive at Bangkok is Thursday and it would be best to avoid Tuesday, as prices are on average 66.43% higher than on Thursday. (Average prices, based on 4846746 datapoints.)
We have a lot more statistics for flights PG 167 and between Bangkok and Koh Samui.