Flights to Koh Samui tend to be extremely expensive due to agreements and a bit of a monopoly from Bangkok Airways on flights to the island. There are direct flights from cities other than Bangkok but all airlines are required to compete with Bangkok Air’s prices.
Flights from Bangkok Suvarnabhumi Airport on Bangkok Airways are only about one hour – do not upgrade to ‘business’ as these flights are either on a propeller plane or an Airbus A319; the only difference between business and economy on these planes is a small curtain that separates the seats.
Expect to pay about $275 roundtrip for flights from Bangkok to Koh Samui.
Getting from the Koh Samui airport
You can arrange a pick up transfer from your hotel prior to arriving in Koh Samui, which tends to be about the same price as getting a taxi at the airport. If you are traveling light, you can also rent mopeds at the airport for very cheap prices ( about $4.50 per day ).