Khao Sok National Park

Khao Sok protects the largest tract of rainforest in southern Thailand — 738 sq km of what is often ranked among the world’s oldest evergreen rainforests, draped over limestone karsts that rise straight out of the canopy. Most visitors come for one thing: Cheow Lan Lake, the emerald reservoir created when the Rajjaprabha (Ratchaprapha) Dam flooded a valley of limestone peaks in 1987. The cliffs jutting from its still water have earned it the nickname “Thailand’s Guilin,” and a night in a floating raft house here is the park’s signature experience.

The lake sits about an hour’s drive from the park’s main entrance on the Surat Thani–Takua Pa road, where most guesthouses cluster in Khao Sok village. From the Rajjaprabha pier, longtail and speedboats fan out to raft-house resorts moored against the cliffs. Days are spent kayaking the flooded valleys, swimming off the deck, and joining guided dawn safaris in search of gibbons, hornbills, langurs, and — with luck and a quiet boat — wild elephants on the shoreline. Caves such as Nam Talu cut through the karst, though guided trips into them close in the wet months when flash floods are a genuine danger.

Back on the mainland side, jungle trails from the headquarters lead to waterfalls and viewpoints, threading through groves where the rafflesia — the giant parasitic “corpse flower,” up to 80 cm across — blooms unpredictably between roughly November and April. Khao Sok is one of only a couple of places in Thailand you’ll find it.

Insider Tip: Book at least one overnight on the lake rather than visiting as a day trip. The boat traffic and tour crowds clear out by late afternoon, and the dawn safari — when the karsts steam and the gibbons start calling — is the moment that makes Khao Sok.

Watch out: Leeches are common on the forest floor after rain. Wear closed shoes and long socks, and carry repellent. The wet season (roughly May–November) brings the lushest jungle and fullest waterfalls but slippery trails and the occasional cave-tour closure.

The driest, most reliable months are December to April. Entry is 300 THB for foreign adults and 40 THB for Thai nationals, paid at the gate, and the park is open daily 08:00–17:00. Khao Sok works well as a two- or three-night break between Phuket or Khao Lak and Koh Samui — it sits almost exactly between the two coasts.