Koh Tachai (เกาะตาชัย), located in the northern part of the Similan Islands National Park in Phang Nga Province, was once hailed as the “Maldives of Thailand” due to its fine, powder-white sand beaches and crystal-clear turquoise waters . However, the island has been closed for ecosystem restoration since 2016 (B.E. 2559) . Yet, what truly made Koh Tachai charming and memorable was its unique biodiversity, especially the Giant Hermit Crab (ปูเสฉวนยักษ์), which has become a distinctive symbol of the island .
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The Giant Hermit Crab: Guardian of the Beach
The Giant Hermit Crabs found on Koh Tachai are Land Hermit Crabs of the genus Coenobita . They are significantly larger than common hermit crabs, often growing to a size where they cannot find a natural seashell large enough to protect their bodies. When fully mature, these Giant Hermit Crabs are famously known to use broken coconut shells as a substitute for a seashell . This unique adaptation is a spectacular sight that many visitors eagerly anticipate.
| Key Characteristics of the Giant Hermit Crab | Details |
| Genus | Coenobita (Land Hermit Crab) |
| Size | Can grow up to about 5 inches when fully mature |
| Shelter | Uses large seashells or coconut shells as a substitute when fully grown |
| Behavior | Nocturnal and an Omnivorous Scavenger |
| Significance | An indicator of the ecological health of Koh Tachai |
These Giant Hermit Crabs play a vital role in the island’s ecosystem, acting as scavengers of organic debris. They emerge from their hiding places at dusk and move along the beaches and mangrove forests in search of food. Witnessing the army of Giant Hermit Crabs moving together is an impressive and unforgettable experience for visitors .
Koh Tachai: A Paradise Awaiting its Return
Beyond the Giant Hermit Crabs, Koh Tachai is also home to other rare animals such as the Hairy Chicken Crab (which is known for making a sound similar to a chicken) and the Emerald Snail (a new species of snail found only on this island) . This natural abundance is precisely what led to the challenges in tourism management and the subsequent closure.
“Koh Tachai was closed for the restoration of its ecosystem, coral reefs, and natural resources that were affected by the large number of tourists in the past.”
Latest Update: Is Koh Tachai Reopening in 2026?
After being closed for over 9 years for restoration, there is exciting news for those awaiting the return of Koh Tachai. Recent reports indicate a meeting to discuss management guidelines and preparations for accommodating tourists, suggesting a strong possibility of reopening for visitors in 2026 (B.E. 2569) .
However, this return will be accompanied by strict measures designed to maintain the delicate balance of nature:
•Tourist Limit: Restricted to no more than 100 people per day
•Visiting Duration: Limited to only 6 hours per day
•Permitted Activities: Focus on low-impact activities such as relaxing on the beach and walking along designated nature trails
This strict limitation on tourist numbers is a crucial step to ensure the sustainable protection of the Giant Hermit Crabs, Chicken Crabs, and the fragile ecosystem of Koh Tachai.