Koh Phangan's Waterfalls and Jungle Trails
Than Sadet, Phaeng and the hikes worth the muddy shoes.
Most of Koh Phangan's reputation is coastal — and the beaches deserve it — but the island's green interior hides something the beach crowds miss: two proper waterfalls, a jungle summit with 360-degree views, and trails that feel genuinely wild. You don't need a guide for most of them, but you do need to start early and wear real shoes.
Phaeng Waterfall — the accessible one
About 7 km north of Thong Sala, Phaeng Noi is the most visited waterfall on the island and for good reason. A short, signposted walk through national park forest leads to a series of tiered pools fed by a clean waterfall — swimmable in the lower pools after rain, more of a trickle in the dry months. The national park entry fee is small; bring cash. It's the right first waterfall if you're only doing one, and an easy half-morning from any southern base. Pair it with a west-coast afternoon at Zen Beach or browse the beaches guide for what's closest to you.
Than Sadet — the royal waterfall
Further east and reached via a rougher track, Than Sadet was a favourite of King Rama V, VII and IX — the smooth granite boulders in the river bear Royal Ciphers carved over more than a century of visits. It's a wilder, less polished experience than Phaeng: a longer walk through denser jungle leading to deep green pools backed by the main falls. Go in the wetter months (roughly June to October) for the best volume and deepest swimming; in the dry season the upper pools shrink but the forest is easier going. The national park boundary starts near the ranger station at the beach — trails fan inward from there.
Khao Ra — the summit
At 627 metres Khao Ra is the island's highest peak, and the trail is one of the more serious hikes Koh Phangan offers. The path is unmaintained in sections — steep, muddy, sometimes overgrown — and best attempted with a local guide or at least detailed directions from your accommodation. Those who make it are rewarded with a clear panorama over the whole island: ocean on every side, jungle below, and on a bright morning the outline of Koh Samui to the south. Start before 8 am to beat the heat and reach the top while the sky is still clear. Several operators under Tours & Nature run guided ascents if you'd rather not navigate solo.
Practical notes
Wear closed shoes — trails are rocky and slippery after rain, and flip-flops are a bad idea on any of these. Carry more water than you think you need; none of the trailheads reliably have vendors. The best conditions are November to April when the trails are drier, but the green season delivers the fullest waterfalls and a wilder atmosphere. A scooter gets you to both waterfalls in a single morning if you're experienced in the saddle; the Phangan Zipline is set in the same canopy above Sri Thanu and pairs well as an afternoon activity. For the full island picture — beaches and interior together — see the diving & snorkelling guide for the underwater side, and the beaches guide for what's worth the drive on the coast.