Khao Sok National Park

Khao Sok shelters what many naturalists rank among the world's oldest rainforests - an ecosystem often dated to some 160 million years, spared the ice ages by Thailand's steady equatorial seat and, by that reckoning, older than the Amazon. The park covers about 739 square kilometres, rising to some 950 metres on its limestone spine, and the rain from both the Gulf and the Andaman makes it one of the wettest corners of Thailand, around 3,500 millimetres a year. The park's theatre is double: dripping lowland jungle where gibbons whoop the dawn and the huge Rafflesia kerrii flower rots gorgeously into bloom, and Cheow Lan Lake - roughly 165 square kilometres of jade water impounded behind the Ratchaprapha Dam - where limestone karsts rise sheer and floating raft-house camps let you sleep on the water itself. Longtail boats thread the drowned towers, kayaks slip across the morning glass, cave treks wade the Nam Talu passage in season, and wild elephants, hornbills and hooting gibbons keep the species count honest. It is southern Thailand's green answer to its own beaches.

What's there

• Cheow Lan raft houses - a night floating beneath the karsts.
• The limestone towers - sheer drowned peaks from a longtail bow.
• Rafflesia in bloom - the giant flower on guided jungle trails.
• Nam Talu cave - the wading torch-lit passage in dry season.

When to go

December to April is driest, though rainforest rain honours no calendar. Rafflesia blooms mostly in the cool months; the lake is photogenic year-round and mistiest at dawn.

What to expect

Lake raft houses book through operators, not walk-ins - plan ahead. Leeches thrive in the wet months, cave routes close after heavy rain, and the famous forest-age figure is a scientific estimate, not a certificate.

Nearby

Khao Lak's coast, Surat Thani and Phang Nga Bay.

Key facts