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 464 datapoints.)
The best day to arrive at Koh Samui is Tuesday and it would be best to avoid Thursday, as prices are on average 29.55% higher than on Tuesday. (Average prices, based on 545 datapoints.)
The best time to fly is at around 16. (Average prices, based on 796 datapoints.)