Namtok Than Mayom

Namtok Than Mayom is a four-tier waterfall inside Mu Ko Chang National Park on the eastern side of Koh Chang, best known for the royal monograms Thai kings carved into its rocks. It’s one of only two waterfalls on the island — alongside Klong Plu — where the national park actually collects its entrance fee.

King Rama V visited Than Mayom nine times between royal tours of the eastern gulf, carving his cipher จ.ป.ร. into the rock and leaving a small stone cairn nearby as a personal marker. King Rama VII and Queen Rambhai Barni visited later and left their own monogram near the upper tier — together the carvings make this one of the more historically documented waterfalls in the country, not just a scenic stop. The water itself flows year-round over black granite in four stepped drops, with the lower pools shallow and calm enough for a swim and the upper tiers reached by a steeper scramble.

Insider Tip: The royal monograms are easy to walk past without noticing — they’re carved into rock faces near the upper pools, not signposted with much fanfare. Ask the ranger at the gate to point you toward them before you start the walk up.

Forest closes in tight around the trail — tall dipterocarp canopy, the kind of humidity that makes the pools genuinely welcome by the second tier. Flow peaks May through October; visit in the dry season (roughly December-April) and the upper pools thin out, though the lower tiers still hold water. Watch out: granite gets slick with algae once wet — water shoes make a real difference on the rock scramble between tiers, and the path back down after rain gets slippery fast.

Entry costs 200 THB for foreign adults (100 THB for children under 14) and 40 THB for Thai adults (20 THB for children), paid at the park checkpoint — this is a genuine, actively enforced national park fee, not a donation box. Gates operate 08:00-16:30 daily; plan your visit to be back at the trailhead before closing since there’s no lighting on the path out. Bring swimwear, water shoes, and a dry bag for anything you don’t want soaked on the walk between pools.