Koh Samui is served by Samui International Airport (USM), a privately owned airport operated by Bangkok Airways. This unique status means the airport has a near-monopoly on scheduled commercial flights into USM, which typically results in higher airfares compared to other Thai destinations. However, it offers convenient direct connections from key regional hubs and domestic cities into Koh Samui.
The airport provides essential domestic flights into Samui from Bangkok's Suvarnabhumi Airport (BKK) and Don Mueang (DMK), as well as from other Thai cities like Chiang Mai (CNX) and Phuket (HKT). Its international network into USM focuses on direct flights from major Southeast and East Asian hubs, including Singapore (SIN), Kuala Lumpur (KUL), Hong Kong (HKG), and cities in China. There are no long-haul intercontinental flights into Koh Samui.
Bangkok Airways is the dominant carrier into USM, operating the vast majority of flights to Samui Airport. Thai Airways also operates a few services into Koh Samui. The limited competition is the primary reason fares into USM are generally higher. Low-cost carriers do not operate to Samui Airport.
Finding truly "cheap" flights to Koh Samui is difficult. To get the best available fares into USM, book as far in advance as possible, especially during peak season (December-August) for Koh Samui. Consider alternative, more affordable routes to reach the island:
Fly to Surat Thani (URT) on the mainland via a ferry+bus combo ticket to Koh Samui (the most budget option to the island).
Take a ferry from Koh Samui to Don Sak pier and then a bus to Surat Thani Airport (URT), from where you can find much cheaper domestic and international flights into the region, though this is for departing Samui — for arriving, reverse the process: fly cheaply to URT, then take bus+ferry to Koh Samui.
If convenience to USM is a priority, book a through-fare to Samui Airport from your final origin, as Bangkok Airways has interline agreements that can simplify baggage transfer for arrivals into USM.