Koh Daeng is situated to the north of the Koh Hong archipelago within the jurisdiction of Than Bok Khorani National Park in Krabi Province. The geological prominence that makes this island a significant landmark is its massive limestone structure rising majestically from the Andaman Sea. The rocks exhibit a unique deep red or brownish-red hue, resembling iron rust, which is caused by the chemical reactions of minerals within the stone. This striking coloration creates a magnificent contrast against the emerald green waters. Although Koh Daeng lacks a sandy beach for visitors to land on, its steep cliffs and underwater rock formations serve as a natural fortress that preserves the integrity of the marine ecosystem.

The waters surrounding Koh Daeng are regarded as one of the premier snorkeling spots on the Koh Hong tour circuit. Thanks to its natural wave-sheltering characteristics, the sea in this area is often calm with high visibility, providing an ideal environment for observing the underwater world clearly. Beneath the surface lies an extensive coral reef system, particularly noted for its dense and healthy staghorn corals. Additionally, massive porites and brain corals provide essential habitats for a diverse range of marine life. Visitors can closely observe schools of sergeant major fish, clownfish living among sea anemones, and parrotfish that play a vital role in processing dead coral.

Beyond its underwater allure, Koh Daeng holds great conservation importance under the supervision of national park rangers who regulate tourist numbers and protect the environment from destructive fishing or careless anchoring. For photographers and nature enthusiasts, the uniqueness of Koh Daeng lies in its scenic red cliffs dotted with salt-tolerant vegetation growing in rock crevices, showcasing the adaptation of life on maritime limestone. Visiting Koh Daeng is therefore not just about snorkeling; it is an opportunity to experience a natural sculpture that has been shaped and eroded over millions of years amidst the tranquility of the Andaman Sea.

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How to Get There

• Visitors can hire a long-tail boat or join a One Day Trip (Koh Hong route) from Noppharat Thara Beach or Ao Nang, which takes about 45-60 minutes. Departing from Tha Len Pier is also a popular and shorter option.

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Travel Tips

• Check the local tide tables in advance to find the best water levels for snorkeling.

• Wear a life jacket at all times while in the water due to occasional strong currents.

• Prepare a high-quality waterproof bag or case for your camera and phone while on the boat.

• Avoid using sunscreens with harmful chemicals and switch to reef-safe alternatives instead.

• Do not touch or step on coral reefs and refrain from feeding any fish in the park.

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Admission Fees:

• Included in the Than Bok Khorani National Park fee.

• Thai Nationals: Adults 60 THB, Children 30 THB .

• Foreigners: Adults 300 THB, Children 150 THB.

Opening Hours:

• Open daily from 08:30 AM – 04:30 PM (May be closed during the monsoon season per National Park announcements, typically July–September).