Ao Tubtim

Ao Tubtim is a small, rock-strewn bay on Koh Samet’s east coast, a short walk south of Hat Sai Kaew, the island’s busiest strip of sand. Rust-red boulders break the shoreline into a handful of smaller coves, and the water is calm enough for swimming in normal conditions. Because the whole island falls inside Khao Laem Ya–Mu Ko Samet National Park, a park entry fee applies here just as it does everywhere else on Koh Samet — 200 THB for foreign adults, 40 THB for Thai adults.

The rocks are the reason to come. They’re a deep rust-orange rather than the pale granite you get elsewhere on the island, and they split the beach into pockets of sand small enough to feel private even when Hat Sai Kaew is busy. Swimming and light snorkelling around the boulders work best on calm days; don’t expect coral-reef visibility, but small reef fish shelter around the rock bases. A scatter of casuarina trees along the back of the beach gives shade without blocking the sea view, and the sand itself is fine and pale where it isn’t broken up by stone.

Watch out: the rocks are slick where waves reach them, and there’s little in the way of lifeguard cover on this stretch — wear sandals with grip if you’re clambering over the boulders, and don’t count on rescue support if you get into trouble swimming.

Ao Tubtim stays quieter than Hat Sai Kaew because it has fewer beach clubs and less through-traffic — most visitors are staying at one of the small resorts set back from this stretch rather than day-tripping in. That makes it a reasonable choice if you want swimmable water within walking distance of Na Dan pier without Hat Sai Kaew’s evening noise. Food options are limited to what your resort serves plus a couple of small beachfront restaurants, so it’s worth eating before you settle in for the day if you’re not staying nearby. The national park visitor point at Khao Laem Ya, on the mainland side of the park, covers the broader protected area Koh Samet belongs to.

Insider Tip: Songthaews between Na Dan pier and the east-coast beaches run on a shared basis with a per-person fare set by route, not distance — confirm the price with the driver before you get in, since rates aren’t posted.