Island geography and orientation
Koh Samui is one of Thailand's largest islands (commonly cited as second after Phuket), about 228 sq km, in the Gulf of Thailand off Surat Thani province. A mountainous, jungled interior is ringed by a coastal road (Route 4169) roughly 50 km around, taking about 1.5 hours to drive non-stop. The busy east coast (Chaweng, Lamai) holds the main tourist beaches and nightlife; the calmer north (Bophut, Maenam, Bang Rak, Choeng Mon) suits families and quieter stays; the west (Nathon, Lipa Noi, Taling Ngam) is the ferry and sunset side, less developed. Samui sits near sister islands Koh Pha Ngan and Koh Tao, both reachable by ferry.
General information, not legal advice. Laws and practice change; for a decision that matters, confirm with the authority named in the sources or a licensed professional.