The best month to fly between Koh Samui and Bangkok is August and the most expensive month to fly is July. (Average prices, based on 536 datapoints.)
The best day to arrive at Koh Samui is Tuesday and it would be best to avoid Thursday, as prices are on average 27.81% higher than on Tuesday. (Average prices, based on 270 datapoints.)
The best time to fly is at around 8. (Average prices, based on 721 datapoints.)