Ang Thong Marine National Park (Mu Ko Ang Thong) encompasses 42 islands in the Gulf of Thailand, roughly thirty kilometers west of Koh Samui. Its limestone formations cloaked in tropical forest, hidden lagoons, and deserted beaches make it a frequent day-trip destination from neighboring islands, with a landscape reminiscent of Ha Long Bay in Vietnam.

Why Visit Ang Thong National Park

The Ang Thong archipelago concentrates a rare diversity of landscapes across 102 square kilometers: limestone outcrops rising from turquoise seas, mangrove forests, sandy beaches, sea caves, and enclosed lagoons. Its national park status protects the wildlife—macaques, monitor lizards, seabirds—and preserves still-intact coral reefs for observation.

Access only through organized excursions limits day-trip footfall and safeguards the integrity of the sites. It ranks among the most sought-after nature outings in the Surat Thani region, complementing a beach stay on Koh Samui or Koh Phangan.

History and Protection

The archipelago was declared a marine national park in 1980, becoming one of the first protected maritime zones in southern Thailand. Previously used as a fishing ground and training area by the Royal Thai Navy, the territory shifted toward conservation to preserve its reefs and terrestrial ecosystems.

Management by the Department of National Parks enforces an annual closure during the wettest season to allow ecosystems to regenerate and ensure safe navigation. This measure accounts for the relatively pristine condition of beaches and lagoons despite sustained tourist traffic.

What to See in the Archipelago

Koh Wua Lap (Koh Wa Talap)

The park's principal and only inhabited island, it houses the ranger station, government bungalows, and the landing beach for excursions. A marked trail leads to a summit viewpoint: allow 1 to 2 hours to climb depending on your pace, with steep rock passages. The panorama sweeps across much of the archipelago.

Koh Mae Koh and the Talay Nai Lagoon

This island's main draw is the Talay Nai lagoon, an emerald expanse roughly 200 meters across encircled by cliffs. Access is via a constructed stairway, which also leads to an overlook above the lagoon. Swimming in the lagoon is prohibited; viewing occurs from the walkways.

Koh Sam Sao and Koh Ling

Koh Sam Sao features a natural arch and good snorkeling spots along its reefs. Koh Ling is recognized by its sculpted rocks resembling a monkey's head—a photogenic formation often pointed out during the crossing.

Activities On-Site

• Snorkeling: reefs accessible from the boat, diverse coral fauna.

• Sea kayaking: exploration of coves and passages between islands, often included in "premium" packages.

• Hiking: climbs of Koh Wua Lap and Koh Mae Koh—short but strenuous.

• Swimming on the beaches of Koh Wua Lap and Koh Sam Sao.

Practical Information

Park entry is charged (separate adult/child rates), typically not included in the excursion price; plan to pay in cash on the boat or at landing. Standard excursions include transport, breakfast and lunch, mask and snorkel; packages with kayaking are slightly costlier.

Bring: reef-safe sunscreen, closed-toe shoes for trails, swimwear and towel, waterproof bag for belongings, extra water, and a light windbreaker for the return. The sun is intense even when overcast.

To spend the night on-site, government bungalows and camping are available at Koh Wua Lap: very basic comfort, advance booking required through the Department of National Parks. A few operators also offer two-day trips with overnight stays aboard.

When to Go

The park closes each year during the monsoon, traditionally from early November through late December, for maritime safety reasons. Exact dates may vary year to year—verify before planning your stay.

The best season runs from late February to May, with calm seas and excellent underwater visibility. From June to October, excursions operate but weather may cause cancellations; waters can be murkier. January remains acceptable but may see blustery days.

How to Get There

The park is not accessible on your own: a visit is exclusively through an organized excursion. Departures are chiefly from:

• Koh Samui: 50 to 60 minutes' crossing—the most convenient option.

• Koh Phangan: 60 to 90 minutes depending on conditions.

• Koh Tao: longer journey, offered by select operators.

Day trips typically depart mid-morning and return mid-afternoon. Boat choice—speedboat or slow boat—affects comfort, time spent on-site, and price.

What to Combine in the Region

• Koh Samui: ideal departure base, lively beaches and temples.

• Koh Phangan: more nature-focused vibe, northern island coves.

• Koh Tao: regional diving hub.

• Elephant Haven Sanctuary: ethical stop in the north if your itinerary extends toward Kanchanaburi.

Frequently Asked Questions

Organizing Your Trip

Ang Thong National Park fits easily into an itinerary combining Gulf islands and the country's south. To build a custom itinerary including this excursion, explore our Thailand travel suggestions.