Tham Khamin, also known locally as “Tham Mhen” (Stinky Cave), is a large limestone cave of significant geological, ecological, and touristic importance. Located within Tai Rom Yen National Park, Surat Thani Province, it is considered one of the grandest cave systems in the South. It is distinguished by its Golden Calcite Formations, resulting from the crystallization of calcium carbonate accumulated over hundreds of thousands of years.

The cave structure is a Multi-chamber Limestone Cave System, totaling approximately 1,250 meters in length, and divided into about 12 main chambers, such as the Curtain Chamber, Buddha Image Chamber, and Pagoda Chamber. Each zone has its own distinct beauty and unique characteristics.

Geologically, Tham Khamin was formed through the process of Karst Topography, resulting from the erosion of underground water in limestone layers, creating large cave hollows, complex passageways, and the crystallization of calcium carbonate, transforming into unique and rare stalactite and stalagmite formations.

The cave is also home to a massive bat population, leading to the accumulation of significant amounts of bat guano and giving rise to its alternative name, “Tham Mhen” (Stinky Cave). It was also a bat guano concession area for over 60 years in the past.

Another significant feature is the old jeep inside the cave, located in the center of the main hall, which was used to transport bat guano. It was brought in disassembled and assembled inside the cave, and remains a historical artifact to this day.

The atmosphere inside the cave is humid and maintains a constant temperature throughout the year, with elevated wooden walkways and a lighting system that enhances safety and highlights the beauty of the golden-colored rocks.

Additionally, the surrounding area features a nature trail in the rainforest area, perfect for in-depth learning about ecosystems, nature, and geology.

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How to Get There

• From Surat Thani city, take Highway No. 4009 towards Ban Na San District. The cave is located on the roadside, approximately 2 kilometers before reaching the district center, with clear signs for Tai Rom Yen National Park.

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Travel Tips

• Wear non-slip shoes as the walkway can be damp in some areas.

• It is recommended to bring drinking water as the trail is quite long, about 1.5 kilometers.

• Allow approximately 1–1.5 hours for the visit.

• It is best to go in the morning to early afternoon for a comfortable walk.

• Refrain from making loud noises to avoid disturbing the bats and the cave ecosystem.

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Fees:

• Thai Citizens: Adults 40 Baht / Children 20 Baht (including National Park entrance fee)

• Foreigners: Adults 200 Baht / Children 100 Baht

Opening Hours:

• Open Daily: 09:00 AM – 3:30 PM