Koh Lidi is situated within the boundaries of Mu Ko Phetra National Park and is a recognized site under the Satun UNESCO Global Geopark. The name "Lidi" is derived from a Malay word meaning "thin stick" or "coconut leaf spine," referencing the long, slender physical appearance of the island chain. The area primarily consists of two main islands: Koh Lidi Yai and Koh Lidi Lek. The topography is characterized by rugged limestone mountains, with the highest peak reaching approximately 137 meters above mean sea level. The islands are covered in lush tropical rainforests and exceptionally well-preserved mangrove forests, serving as a sanctuary for various waterfowl and bird species, while the limestone caves provide natural nesting grounds for the local swiftlet population under official concession.

Geologically, Koh Lidi is of immense significance due to the presence of Paleozoic fossils embedded within its sedimentary rock layers. Visitors can explore the coastline to witness Mahachai limestone and shale formations that date back hundreds of millions of years. A notable geological feature is the "Rock Railway" (Thang Rot Fai Hin), an extraordinary phenomenon where marine erosion has carved parallel grooves into the rock strata, resembling train tracks. Furthermore, during low tide, a natural sandbar emerges, creating a "Talay Waek" (parting sea) effect that connects Koh Lidi Lek and Koh Lidi Yai. This allows hikers to walk between the two islands to closely observe the transition between marine and terrestrial ecosystems.

Currently, the island serves as the location for the National Park Ranger Station (Phet Phum 1), which ensures the safety and well-being of all visitors. The island offers developed nature trails that wind through mangroves and rocky shorelines. Popular activities include kayaking to explore hidden sea caves and overhanging limestone cliffs, as the surrounding waters remain clear and calm throughout most of the year (excluding the monsoon season). Despite its proximity to the bustling Pak Bara Pier—only a few kilometers away—Koh Lidi has maintained its pristine tranquility. It remains a premier destination for eco-tourists and researchers interested in deep geological history and those seeking an authentic, peaceful Southern Thai island experience.

• Hire a long-tail boat from Pak Bara Pier; the journey takes approximately 15–20 minutes. Alternatively, book a local tour package that includes kayaking and visits to nearby islands.

• Visit during low tide to see the sandbar connecting the two islands

• Always check tide schedules before your trip

• Depart from Pak Bara Pier for the most convenient access

• The best time to visit is November–April for clear water and calm seas

Admission Fees:

• Thai Citizens: Adults 20 THB, Children 10 THB 

• Foreigners: Adults 200 THB, Children 100 THB (National Park entry fee)

Opening Hours:

• Open daily from 09:00 AM – 05:00 PM (Closed during the monsoon season, typically from May to October)