Susan Hoi Fossil Shell Beach

Susan Hoi — literally “shell cemetery” — is a stretch of shoreline at Ao Nam Mao, Krabi, where slabs of solid limestone are packed with fossilized freshwater snail shells. Entry is 200 THB for foreign adults, open daily roughly 08:00-16:30. The name most visitors know it by, “75 million years old,” doesn’t hold up: pollen and spore analysis of the rock dates the beds to around 40 million years, placing them in the Cenozoic era rather than the Cretaceous. The old figure stuck anyway and still appears on most signage and tour listings, so both names are worth knowing.

What you’re looking at is an ancient freshwater lakebed. Millions of small snails settled in the shallows, died, and were compressed into “shelly limestone” over deep time — the slabs along the shore are dense with their outlines, some individual, some fused into solid sheets over 40 cm thick. It’s genuinely unusual: sources describe this as one of only three comparable shell fossil sites known worldwide, alongside examples in the United States and Japan, though that count comes from Thai tourism sources rather than an independent geological survey. The formations run along a short section of coast within Hat Noppharat Thara-Mu Ko Phi Phi National Park, ticketed at their own booth rather than through the general park gate.

A visit is short — a flat walkway lets you get close to the rock without scrambling, and most people are through in 30-45 minutes. The surface is uneven and can be slick near the waterline, so trainers with grip beat sandals. There isn’t much shade, and the fossil beds sit exposed to full sun for most of the day.

Insider Tip: Go at low tide. High water covers a good portion of the fossil slabs, and the light is flatter for photos in the middle of the day — early morning gives softer light and exposes more of the shell patterns.

Watch out: Midday heat here is unshaded and reflects off the pale limestone. Bring water and a hat, and budget 15-20 minutes less than you’d plan if you’re visiting between 11:00 and 14:00.

The site is a short drive from Ao Nam Mao, on the same stretch of coast as Noppharat Thara Beach and the wider Hat Noppharat Thara-Mu Ko Phi Phi National Park, both a few minutes further along the road toward Ao Nang.