Road safety basics: driving on the left and local road behaviour

For visitors from right-hand-traffic countries, left-hand driving is the single biggest adjustment, and it matters most at junctions, roundabouts and when pulling out, the exact moments when instinct points the wrong way. Koh Samui's main road is a single ring road (Route 4169/4170) circling the island, with most beaches and attractions directly off it. Expect: scooters overtaking on both sides and appearing suddenly; sand, gravel, oil patches and potholes on corners; unmarked speed bumps; dogs and pedestrians on the road; winding hill sections, notably between Chaweng and Lamai, where a small roadside memorial marks past traffic deaths and passing drivers beep their horns as a sign of respect; and heavy rain making everything slick, with accident rates rising in wet months. Practical rules: drive slowly and defensively, assume other road users may not signal, check mirrors constantly for scooters, never drive or ride after drinking, keep headlights on, park fully off the tarmac at viewpoints because the ring road curves and traffic moves fast, and never park beside red-and-white painted curbs. If you hire a car, carry your licence, IDP and rental papers because police checkpoints occur. If you are involved in an accident, do not move injured people unless there is immediate danger, photograph the scene and plates, call 1669 for injuries and 191/1155 for police, and get the police report slip for insurance.

Summary

Thailand drives on the left. If you rent a car or scooter on Koh Samui, expect left-hand traffic, scooters appearing from all directions, sand and potholes on corners, few central barriers, and local habits like horn-beeping at the roadside memorial hill. Slow down and drive defensively.

Key facts

• Thailand drives on the left; take extra care at junctions and roundabouts
• One main ring road (4169/4170) circles the island
• Hazards: scooters everywhere, sand on corners, potholes, dogs, unmarked bumps
• The Chaweng-Lamai hill is a known accident blackspot with a memorial
• Carry licence, IDP and rental documents; checkpoints occur
• After an accident: 1669 for injuries, photos, police report slip for insurance

Local tips

• New to left-hand driving? Practise first in a quiet area or car park
• Rain doubles the risk; slow down and increase distance
• Park fully off the road at viewpoint pull-offs
• Red-and-white painted curbs mean no parking