Updated: May 2026
Spanish · 5 years on Samui
Spanish cycling enthusiast and eco-travel advocate on Koh Samui for 5 years. Carlos covers all bicycle and e-scooter content with a focus on sustainable exploration.
I have circled Koh Samui by scooter, by car, and twice by bicycle. The bicycle version is the slowest and by far the most revealing. At 20 km/h you notice things that disappear at scooter speed - the smell of the tamarind trees above Lamai, the sound of the monks' morning chanting drifting through the jungle, the exact moment when the road surface changes from resort-maintained smooth to everyday Thai rough. The ring road on a Trek Marlin 5 is not a faster way to see Samui. It is a deeper one.
Circumnavigating Koh Samui by bicycle is 51 km of ring road plus the inevitable detours to beaches that sit below the main road. I split the loop over three days: south coast on day one (Chaweng to Thong Krut, 22 km), west coast on day two (Thong Krut to Nathon and up to Mae Nam, 18 km), and the north coast return on day three (Mae Nam to Chaweng, 14 km with stops). Each day ends at a beach. I planned it on a December morning when the humidity was manageable and the wind was coming from the northeast.
The ring road has three significant climbs. The Nathon heights on the west coast are the longest and most sustained - I ground up them in second gear on the Trek Marlin 5 for about eight minutes before the view justified the effort. The southern headland above Hua Thanon is shorter but steeper. The inland cut between Mae Nam and Chaweng is the sneaky one - it looks flat on the map but gains 60 metres in two kilometres. Geared appropriately on a 21-speed MTB, none of these is impossible.
Between Lamai and Thong Krut there are no convenience stores for approximately 11 km. I carried two 750 ml bottles and ran dry by the Samui Skate Park junction. A local family sold me a cold bottle from their roadside cooler for 20 baht and I have bought from them every time I have ridden that stretch since. The pattern on this island is that where scooter renters stop, cyclists are ignored; where the road thins and the trucks disappear, locals are generous in a quiet, uncomplicated way.
The ring road's satellite view hides the quality difference between the east and west coast tarmac. The east coast from Chaweng to Lamai is smooth and wide, maintained for resort traffic. The west coast from Nathon north is rougher, narrower, and occasionally interrupted by drainage channels with no warning humps. The Giant Talon 3's 29-inch wheels roll over these transitions better than a hardtail with smaller wheels would - it was on the Talon that I first noticed how much wheel diameter matters on rough asphalt.
The north coast road through Bang Rak and Choeng Mon has raised traffic islands that are invisible at cycling speed until they are directly in front of you. I hit one at dusk on day three on the Trek Marlin 5 and the front disc stopped me without incident, but I had not been watching carefully enough. After dark, these islands are lit by a single reflector. Slow to 15 km/h through any intersection on the north coast after sunset and use the lights that come standard on every bicycle we rent.
The Trek Marlin 5 and Giant Talon 3 are both well-suited to the ring road loop - 21-speed gearing handles every climb and the 29-inch wheels roll efficiently on tarmac. For the full three-day challenge with loaded panniers, I would recommend the Cannondale Trail SL 4: at 12.5 kg it is the lightest bicycle in the fleet and the weight saving is meaningful over a cumulative 55 km across three days. The Merida Big.Nine 15 is the budget option and capable - just heavier on the sustained climbs.
I have ridden the full Koh Samui ring road dozens of times. This is the exact route I recommend to every renter - start times, fuel stops, and the bends worth slowing down for.
Forget the ring road. The backroad between Mae Nam and Bo Phut runs through coconut farms and fishing villages with almost no traffic. I ride it every week.
The climb to the Big Buddha viewpoint is Samui's most rewarding road - if you take the right approach. Here is how I tackled it safely on a 125cc scooter.
