Koh Samui Airport has regular flights from Bangkok,
Chiang Mai and Phuket and then it's a short boat crossing
to Koh Tao.
The southern rail link, departing from Hualumpong Station
Prachuap Kiri Khan
Chumphon (for Koh Tao)
Surat Thani (for Koh Samui, Koh Phangan,
All government southern bus routes depart from the Southern
Bus Terminal ("Sai Dai Mai") in Bangkok and
have direct routes to Chumphon.