The best month to arrive at Koh Samui is November and the most expensive month to fly is August. (Average prices, based on 780 datapoints.)
The best day to arrive at Koh Samui is Wednesday and it would be best to avoid Friday, as prices are on average 73.65% higher than on Wednesday. (Average prices, based on 814 datapoints.)
At Koh Samui the most flights depart around 16:00. (Hourly flights, based on 853 datapoints.)