Tat Yai Waterfall

Tat Yai Waterfall drops in two stages inside Nam Nao National Park, on the Phetchabun side of the border with Khon Kaen’s Phu Pha Man district. The lower tier is a 20-metre-wide rock apron that steps down for roughly 100 metres; above it, a sheer cliff face about 100 metres high sends the main flow down through dense forest on both banks.

The rock itself is the reason geologists visit as much as photographers do. The stepped layers are fine sedimentary rock laid down over centuries in an ancient freshwater lake, part of the Huai Hin Lat Formation within the wider Khorat Plateau geological sequence — alternating bands of shale, siltstone, and mudstone that erosion has carved into the current stair-step shape. Fossil-hunters know the wider Nam Nao area for dinosaur trace finds in the same rock sequence.

Water volume swings hard with the seasons. Rainy season, roughly May through August, is when the cliff runs as a full curtain and the lower steps fill with cascading pools — the effect the waterfall is known for. By the tail end of the dry season the upper drop can thin to a trickle, though the stepped rock still holds shallow pools worth a look.

Insider Tip: Combine the trip with Nam Nao National Park’s other waterfalls on the same park ticket — the gate fee covers the whole park for the day, not just this one spot.

Watch out: The stepped rock is slick even when it looks dry, thanks to a constant fine spray. Falls here are a real risk — wear shoes with actual grip, not sandals.

Getting There

Tat Yai Waterfall is located at Nam Nao, Phetchabun. View on Google Maps.