Khao Sok National Park

Covering an area of 739 km², including the 165 km² Cheow Lan Lake, Khao Sok National Park is a habitat even older than the Amazon rainforest.

Established in 1980, it’s a place of amazing biodiversity with approximately 200 different floral species per hectare and a huge abundance of wildlife including 48 mammal species, 311 different species of birds, over 30 species of bats and countless reptiles and insects. It’s particularly famous for its limestone karst mountains which dominate the skyline and rise to nearly 1,000m in some areas, with the general topography varying between 200m and 400m above sea level. West of Khao Sok National Park is Sri Phang Nga National Park, which extends the preservation area to 4,000 km². Continuing to the south across Highway 401 is Khlong Phanom National Park, which protects another 410.4 km² within the Phuket mountain range.

280 – 225 Million Years Ago
Khao Sok’s dramatic limestone cliffs were once part of a vast coral reef system stretching across much of Asia during the Permian period. This prehistoric reef was estimated to be five times the size of the Great Barrier Reef. Over millions of years, geological shifts and erosion transformed the seabed into towering karst formations. Even today, marine fossils can be found at the peaks of these cliffs, serving as a reminder of the region’s ancient underwater past.

37,000 BCE
During the Ice Age, lower sea levels allowed humans and wildlife to migrate from what are now Borneo, Sumatra, and Malaysia into southern Thailand. This led to the first human settlements in Khao Sok, where nomadic hunter-gatherer communities thrived within the dense forests. The Sakai people, who still inhabit remote parts of the Thai-Malay border and Sumatra, are believed to be the descendants of these early settlers.

2,500 – 1,300 Years Ago
Ancient trade routes once passed through the narrow Isthmus of Kra, linking merchants from the Greek and Roman empires to Southeast Asia. Instead of sailing around the Malay Peninsula, traders transported goods overland between the Andaman Sea and the Gulf of Siam. Archaeological discoveries in and around Khao Sok, including Persian pottery, Chinese porcelain, and coins with ancient Indian inscriptions, indicate the area’s historical importance in global commerce.

1800s
As Burmese invasions ravaged Thailand’s coastal settlements, many locals fled inland and found refuge in the mountains of Khao Sok. The region’s lush forests and rich biodiversity provided them with food and shelter, allowing communities to flourish. Farming, particularly rice cultivation, became an essential part of life in the surrounding lowlands.

1970s
Khao Sok’s dense jungles became a stronghold for student activists and communist insurgents fleeing political persecution in Bangkok. The rugged terrain and deep caves provided ideal hideouts, making it nearly impossible for the military to drive them out. Ironically, their presence deterred logging, mining, and poaching—preserving the pristine rainforest that still exists today.

1980 – 1987
In 1980, Khao Sok was designated a national park to protect its rich ecosystem. However, just two years later, the Thai government and the Electricity Generating Authority of Thailand (EGAT) approved the construction of Ratchaprapha Dam. Completed in 1987, the 94-meter-high dam flooded the valleys, creating the breathtaking Cheow Lan Lake. The project displaced 385 families from Ban Cheow Lan village and led to the loss of over 50 species of fish that could not survive in still waters. While the dam drastically altered the region’s ecosystem, the resulting lake is now one of Thailand’s most scenic landscapes, attracting visitors from around the world.