The best month to arrive at Koh Samui is November and the most expensive month to fly is August. (Average prices, based on 535 datapoints.)
The best day to arrive at Koh Samui is Thursday and it would be best to avoid Sunday, as prices are on average 21.09% higher than on Thursday. (Average prices, based on 7400 datapoints.)
At Koh Samui the most flights depart around 09:00. (Hourly flights, based on 585 datapoints.)