TALAY NAI · CHEOW LAN LAKE
500 Rai Inner Lake
A secluded inner lake reached from Cheow Lan Lake, where the journey continues through the forest and across the water by bamboo raft.
Bamboo rafts are used to travel across the inner lake after reaching it on foot from the main lake.
500 RAI AT A GLANCE
What Is the 500 Rai Inner Lake?
The 500 Rai Inner Lake, known locally as Talay Nai, is a body of water hidden behind the limestone mountains of Cheow Lan Lake. Although it lies within the same landscape, you cannot simply continue into it by longtail boat.
The usual approach is by boat across Cheow Lan Lake, followed by a walk through the forest to reach the inner lake. From there, bamboo rafts are used to cross the water. For most visitors, this journey forms part of the route to Coral Cave.
That is why 500 Rai is sometimes mistaken for little more than a stop on the way to the cave. In reality, the inner lake is a distinct landscape of its own, surrounded by forest, limestone ridges and narrow waterways that change noticeably with the water level.
LOCAL NAME
Talay Nai (ทะเลใน)
LOCATION
Cheow Lan Lake
ACCESS
Boat, forest walk & bamboo raft
BEST KNOWN FOR
Coral Cave Route
UNDERSTANDING THE AREA
Where Is the 500 Rai Inner Lake?
The 500 Rai Inner Lake is not another bay that branches directly off Cheow Lan Lake. It sits beyond the main lake, separated by forest and limestone terrain, which is why reaching it involves both travelling by boat and continuing on foot.
After crossing the forest, the trail reaches Talay Nai.
From here, the journey continues across the inner lake by bamboo raft.
THE NAME
Why Is It Called “Talay Nai”?
Talay Nai (ทะเลใน) is the Thai name commonly used for the 500 Rai Inner Lake.
In Thai, talay means “sea”, while nai means “inside” or “inner”. Despite the name, Talay Nai is not a sea. It is an inland body of water lying beyond the main reservoir, enclosed by forest and limestone mountains.
The name makes more sense once you make the journey there. After travelling across Cheow Lan Lake and crossing the forest on foot, water appears again on the other side — a separate inner lake hidden within the mountains.
THE NAME
Why Is It Called “500 Rai”?
The name “500 Rai” refers to the Thai unit of land area, rai. One rai equals 1,600 square metres, so 500 rai is equivalent to about 800,000 square metres, or 0.8 square kilometres.
The name has long been used locally for this inner-lake area, but explanations of exactly how the figure of 500 rai was originally established are not consistent.
Rather than treating the number as a precise measurement of the lake as it appears today, it is better understood as the established name of the area. The visible extent of the water can also change with reservoir levels and seasonal conditions.
500 RAI
1 rai
= 1,600 m² 5
500 rai
= 800,000 m²
= 0.8 km²
GETTING THERE
Why You Cannot Just Take a Boat In
Reaching the 500 Rai Inner Lake is different from visiting most places on Cheow Lan Lake. A longtail boat can take you across the main reservoir, but it cannot continue all the way into Talay Nai.
The boat journey ends on the Cheow Lan Lake side of the mountains. From there, visitors continue on foot along a forest trail before reaching the inner lake on the other side.
At Talay Nai, the journey changes again. Bamboo rafts are used to travel across the water, including on the usual route towards Coral Cave.
This combination of longtail boat, forest trail and bamboo raft is what makes reaching 500 Rai different from simply travelling to another bay on Cheow Lan Lake.
LONGTAIL BOAT
Across Cheow Lan Lake
FOREST TRAIL
Cross the mountain on foot
500 RAI INNER LAKE
Arrive at Talay Nai
BAMBOO RAFT
Continue across the inner lake
THE LANDSCAPE
Forest, Limestone & Wildlife
Aerial view of the 500 Rai Inner Lake surrounded by tropical rainforest and limestone mountains in Khao Sok
Talay Nai from above — an enclosed landscape of water, limestone and tropical forest.
Exposed shoreline, tropical vegetation and dead tree trunks at the 500 Rai Inner Lake in Khao Sok
Photos by น้าพล คนเมืองแปด
The 500 Rai Inner Lake sits within the forested limestone landscape of Khao Sok. Around the water, steep slopes are covered in tropical vegetation, with trees and dense undergrowth reaching close to the shoreline in many places.
The character of the inner lake changes with the terrain. Some sections open into wider water surrounded by limestone mountains, while others narrow between forested slopes. Water levels also affect what you see along the shoreline, including exposed banks, tree trunks and partially submerged vegetation.
The surrounding forest supports a wide range of wildlife. Monkeys, squirrels, hornbills, kingfishers and other forest birds may be seen in the wider Cheow Lan Lake area, while signs of wildlife are often easier to notice than the animals themselves.
Wildlife sightings are never guaranteed. Much depends on the time of day, weather, season and simple chance.
WILDLIFE
Animals may be present around the forest, but sightings depend on conditions and luck.
LIMESTONE
Steep limestone formations shape the narrow valleys and enclosed character of Talay Nai.
BIRDLIFE
Hornbills, kingfishers and other forest birds occur throughout the wider lake landscape.
TROPICAL FOREST
Dense vegetation covers much of the limestone terrain around the inner lake.
SEE 500 RAI DIFFERENTLY
Beyond the Usual Crossing
Most visits to 500 Rai are built around the journey to Coral Cave. Beyond 500 Rai takes a different approach, using more of the day to experience the inner lake itself.
Travel privately across Cheow Lan Lake, continue through the forest, and spend more time exploring Talay Nai by bamboo raft — without adding the usual Coral Cave visit.
Frequently Asked Questions
Practical answers to common questions
about visiting the 500 Rai Inner Lake.
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