By Air :
Bangkok Airways is the fastest, easiest and most convenient way to reach Koh Samui. Estimated flight time from all parts of Thailand is about 1-2 hours. There are many hourly connections from Bangkok, Phuket, Krabi, Chiang Mai and Pattaya direct to Samui International Airport as well international flights from Kuala Lumpur, Singapore, Hong Kong and China. The cheaper option is to fly via Surat Thani (mainland nearest Airport) with Nok Air, Thai Air Asia or Thai Lion Air. You can book combination tickets which includes the Flight + bus + ferry to Samui or just book the ferry and bus at the Surat Thani airport.
Special Note:- Bangkok Airports (2) Suvarnabhumi (Main International Airport) and Don Muang (Low Cost Airport) are separate airports in different parts of the Bangkok area and please allow plenty of travelling time between connections.
By Bus :
Public bus, vip coaches are very easy. Several companies have established connections around Thailand. Buses run several times daily from Bangkok (Southern Bus Terminal) or Lomprayah Company located at Ko San Road Bangkok. The travel time by bus is estimated 12 hours. The crossing by ferry takes another 1.5 hours.
Travelling from Phuket, Krabi and Koh Phi Phi, Hat Yai to Koh Samui by bus takes about 4-5 hours and costs is approximately 600 Thai baht including Ferry Tickets.
By Train :
The night sleeper train from Bangkok to Surat Thani is a comfortable, exciting and an easy way to travel which takes about 15 hours from Bangkok to Koh Samui. The journey includes Train, Bus and Ferry. The combined tickets can be booked in many travel agencies in Bangkok or directly at the train station in Bangkok (Hua lamphong Railway Station). It is recommended to choose an air-conditioned sleeper and book your tickets in advance as demand is high anytime of the year.