The Trang islands are a group of small, quiet islands off Trang province, south of Koh Lanta: Koh Ngai, Koh Kradan and Koh Mook are the three most visitors know. You reach them by boat from Pak Meng or Hat Yao piers near Trang, or, in the dry season, by the island-hopping speedboats that run between Koh Lanta and Koh Lipe.
None of these islands has the crowds of Phi Phi or the nightlife of Lanta's Long Beach. They have a few resorts each, clear water, small fishing villages on some of them, and limestone cliffs on the horizon. They are also stepping stones: in season, you can travel from Lanta to Lipe down the coast and stop on one or two Trang islands on the way.
Two different national parks look after them. Koh Mook and Koh Kradan are part of Hat Chao Mai National Park, Trang's coastal park. Koh Ngai, although it lies off Trang, belongs to Mu Ko Lanta National Park. That affects the fee, as explained below.
The Trang islands at a glance
- Main islands
- Koh Ngai (Koh Hai), Koh Kradan, Koh Mook (Ko Muk), plus Koh Libong and Koh Sukorn farther south
- Mainland piers
- Pak Meng (main pier for Kradan, Mook and Ngai), Hat Yao, Khuan Tung Ku
- Nearest town and airport
- Trang, with an airport and a railway station
- Parks
- Hat Chao Mai National Park (Mook, Kradan); Mu Ko Lanta National Park (Ngai)
- Best months
- December to May, according to TAT; island-hopping boats mainly in the dry season
Koh Kradan: the beach island
Koh Kradan is the one people come to for the beach. Its long, white east-facing beach looks across clear, shallow water toward the mainland, with coral close to shore in places. There is no village of any size, only a handful of resorts and bungalows, and the island has a Hat Chao Mai National Park ranger station.
Kradan is for doing very little: swimming, snorkeling off the beach, reading in the shade. There is almost nothing to buy, so bring cash and anything you need. Paths cross the island to a quieter west-facing cove, popular for sunset. If you want a beach that looks like the posters and do not need restaurants within walking distance, Kradan is the pick of the three.
Koh Mook and the Emerald Cave
Koh Mook is larger and has a real fishing village on its east side, with small shops, simple restaurants and guesthouses. It feels more lived-in than its neighbors, which many visitors like. Beaches on the west side, such as Farang Beach, are where most resorts are. The Department of National Parks notes the seagrass beds around the island, which feed dugongs, and in June 2026 park researchers reported a dugong off Koh Mook.
The island's famous sight is Tham Morakot, the Emerald Cave, which TAT lists as one of Trang's main attractions. The DNP describes it as a collapsed sinkhole (a doline) reached through a sea cave. You swim or wade through a dark tunnel in the cliff with a guide and come out in a hidden lagoon: a small beach surrounded by high rock walls, open to the sky.
- The tide decides. The tunnel can only be passed at certain water levels, roughly low to mid tide. Boat drivers time their trips around it.
- It is dark inside. Guides use torches and lead you in a line. Wear a life jacket, even if you swim well.
- Go early or late. Midday is when tour boats from Lanta and the mainland arrive. A longtail from Koh Mook in the early morning usually means a quieter lagoon.
Do not try the Emerald Cave tunnel without a guide or a life jacket. It is pitch-dark, the swell can push you against the rock, and the passage is only open at the right tide. Go with a local boat and guide, who know when it is safe.
Koh Ngai: resorts and shallow water
Koh Ngai (also written Koh Hai) is the northernmost of the three and the closest to Koh Lanta. The DNP describes it as having a long sandy beach on the east side, a bay to the south and steep hills to the north-west, rising to 198 meters. The island is given over almost entirely to resorts, with a national park ranger station; there is no village in the sense of Koh Mook.
The east beach has shallow, calm water in the dry season, which makes Koh Ngai a good choice for families who want a resort stay. In December 2025, rangers reported a dugong feeding near the island and asked boat drivers to slow down; sightings are rare, so do not expect one.
Because Koh Ngai belongs to Mu Ko Lanta National Park, it falls in that park's special zone, where foreign adults pay 400 baht (October 2026), the same rate as Koh Rok. Koh Mook and Koh Kradan are in Hat Chao Mai, a Category 2 park where foreign adults pay 200 baht. Island-hopping tours usually include the fees; if you arrive independently, ask your resort how the fee is collected and keep the receipt.
Koh Libong, Koh Sukorn and the snorkeling islets
Farther south, two larger islands see far fewer foreign visitors. TAT calls Koh Libong the largest island in Trang's sea, surrounded by seagrass beds that support dugongs. Koh Sukorn, the second largest, lies only about 3 km from the shore and has more than 2,500 villagers, according to TAT. Both are places for village life, cycling and quiet, not for resort beaches.
Near Koh Mook and Koh Kradan lie the small islets of Koh Chueak and Koh Waen, which TAT names as popular snorkeling and diving spots with colorful coral. They feature on most day trips.
Island-hopping from Koh Lanta to Koh Lipe
In the dry season, the Trang islands sit on a speedboat route down the coast. The operator Tigerline lists stops at Koh Lanta, Koh Ngai, Koh Kradan, Koh Mook, Koh Libong and Koh Bulone on the way to Koh Lipe, and gives 120 to 150 minutes for the direct Lanta–Lipe run, with up to four trips a day. On the islands without piers, the speedboat stops offshore and longtails carry passengers and bags to the beach.
This route depends on the season. Boats to Koh Lipe from Lanta and the Trang coast run mainly in the high season, roughly October to June, while in the low season Lipe is reached mainly from Pak Bara on the mainland. Operators adjust timetables by season and weather, so check sailings for your dates before you build an itinerary around them. Our Koh Lipe guide and the older article on how to get to Koh Lipe cover the last leg and arrival.
Pack for a beach landing. On Kradan and Ngai, you will often climb from a speedboat into a longtail and then wade ashore. Use a bag you can carry, keep electronics in a dry bag, and wear shoes you can get wet.
From the north, the route starts on Lanta; our Koh Lanta guide covers the island, and getting from Krabi to Koh Lanta explains the first leg. The planned route guide from Phuket to Koh Lipe puts the whole trip together.
From Trang town: piers, flights and trains
Outside the island-hopping season, or if you are coming from Bangkok, start in Trang. The town has an airport with domestic flights and a railway station on the southern line; our guide to Thailand's night trains covers the overnight option. Tigerline, among others, runs shuttle buses from Trang airport and the railway station to the piers.
The DNP names Pak Meng pier, about 40 km from Trang town, as the main pier for Koh Kradan, Koh Mook and Koh Ngai, with boats for charter daily. Hat Yao pier is the other main departure point; TAT describes it as a major ferry port for the Trang islands. In the monsoon, expect fewer boats and rougher crossings from both.
If you are traveling from Malaysia, Trang is also reached by road via Hat Yai. Our overview of ferries in Thailand covers booking and safety on small boats.
When to go
TAT gives December to May as the best time to visit Trang and notes that seasons are not sharply defined: some resorts stay closed into mid-November, while others start charging high-season rates in October. From about May to October, the southwest monsoon brings rain and swell to the whole Andaman coast. Some island resorts close, snorkeling visibility drops, and the Lanta–Lipe speedboats run less or not at all. Our page on the best time for the Thai islands compares the seasons.
For more islands in the same part of Thailand, see our overview of the lesser-known Andaman islands.
Frequently asked questions
Which Trang island is best: Koh Kradan, Koh Mook or Koh Ngai?
Choose Koh Kradan for the best beach and the most peace, Koh Mook for a village, cheaper food and the Emerald Cave, and Koh Ngai for a family resort stay with calm, shallow water. Many visitors split a week between two of them.
How do you get to the Emerald Cave on Koh Mook?
By boat to the cliff entrance, then swimming or wading through a dark sea tunnel with a guide into the hidden lagoon. Access depends on the tide, roughly low to mid tide. Day trips from Lanta and the Trang piers include it, and longtails go from Koh Mook itself.
Can you travel from Koh Lanta to Koh Lipe via the Trang islands?
Yes, in the dry season. Speedboats run down the coast with stops at Koh Ngai, Koh Kradan and Koh Mook, and you can break the journey on any of them. In the monsoon, services are reduced or stop, and Lipe is reached mainly from Pak Bara.
Is there a national park fee on the Trang islands?
Yes. Koh Mook and Koh Kradan are in Hat Chao Mai National Park, where foreign adults pay 200 baht. Koh Ngai is in Mu Ko Lanta National Park's special zone, where foreign adults pay 400 baht (October 2026). Tours usually include the fee.
Are there ATMs on the Trang islands?
Do not count on them. These are small islands with few services, and many places take cash only. Withdraw enough money in Trang, Lanta or another larger town before you go, and keep some in reserve for boat transfers.
Sources
- Department of National Parks – Hat Chao Mai National Park (checked October 2026)
- Department of National Parks – Mu Ko Lanta National Park (Ko Ngai group) (checked October 2026)
- Tourism Authority of Thailand – Trang (checked October 2026)
- Department of National Parks – Dugong feeding near Koh Ngai, 9 January 2026 (Thai) (checked October 2026)
- Department of National Parks – Dugong surveyed off Koh Mook, 9 June 2026 (Thai) (checked October 2026)
- Tigerline Ferry – Official timetables and pricing structure (checked October 2026)
- Kapook Travel – National park entry fees by park and special zone, citing DNP (Thai) (checked October 2026)