Koh Ngai (also spelled Koh Hai) is a small, quiet island off the coast of Trang province, just south of Koh Lanta. It has one long white-sand beach on its east coast, shallow turquoise water, coral close to shore and a handful of resorts — no roads, no town and almost no nightlife.
Most visitors see Koh Ngai on a 4 Islands boat tour from Koh Lanta, but it is also a lovely place to stay for a few nights. This guide explains how to get there, what to do, where to stay and how to fit the island into a Koh Lanta or Krabi trip.
Koh Ngai is a small island in Trang province, about 1 hour by speedboat from Koh Lanta. It is best known for its long east-coast beach and easy snorkelling. Visit on a 4 Islands tour from Koh Lanta, or stay overnight at one of its resorts; boats also run from Pak Meng pier in Trang.
- Province
- Trang (just south of Krabi's Koh Lanta)
- From Koh Lanta
- About 1 h by speedboat (tour or seasonal boat)
- From Trang
- About 30–45 min by boat from Pak Meng pier
- Best for
- Beach, snorkelling, quiet stays
- Best time
- Dry season, roughly November–April
Day trip from Koh Lanta
Compare 4 Islands tours that stop at Koh Ngai, Emerald Cave and Koh Kradan.
Where is Koh Ngai?
The island lies in the Andaman Sea off the Trang coast, part of the Mu Ko Phetra and Hat Chao Mai area of southern Thailand. Although it belongs to Trang province, it is closer to the southern tip of Koh Lanta than to many places on the Trang mainland, which is why most tour boats from Koh Lanta include it.
Neighbouring islands include Koh Muk (home of the Emerald Cave), Koh Kradan and Koh Chueak. Together they form the classic “Trang 4 Islands” route.
Koh Ngai beaches and snorkelling
The main beach runs along most of the east coast. The sand is fine and white, the water is calm in the dry season, and the slope is gentle, which makes it good for families. Coral and small reef fish start a short swim from the shore, especially around the rocky headlands at the north and south ends of the beach.
- East-coast beach — the long main beach, with the resorts set back under the trees.
- Northern headland — rocks and coral; best for snorkelling at mid to high tide.
- Southern end — quieter stretch, good for a walk at low tide.
Snorkelling tip
Bring your own mask if you can. Snorkel at mid to high tide, keep off the coral and use reef-safe sunscreen.
Koh Ngai day trip from Koh Lanta
The easiest way to visit is a 4 Islands tour from Koh Lanta. Tours usually combine the Emerald Cave on Koh Muk, snorkelling stops, lunch on a beach and time on Koh Ngai, with hotel pickup on Koh Lanta. Speedboat tours are faster and spend more time at the islands; longtail tours are slower but cheaper and more relaxed.
| Tour type | Time on the water | Good for |
|---|---|---|
| Speedboat 4 Islands | Shorter crossings | Seeing more in one day |
| Longtail 4 Islands | Longer crossings | Budget, slower pace |
| Private longtail | Flexible | Couples, families, photographers |
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For other boat trips, see our things to do in Koh Lanta guide and the Koh Rok snorkelling tour.
How to get to Koh Ngai
- From Koh Lanta — join a 4 Islands tour, or take a seasonal speedboat heading south (some boats to Koh Lipe stop at the Trang islands; check stops when booking).
- From Trang — fly or take the train or bus to Trang, transfer to Pak Meng pier, then take a boat to the island. Many resorts arrange the transfer.
- From Krabi — travel to Koh Lanta first, or go overland to Trang and Pak Meng.
- From Koh Lipe — seasonal speedboats heading north to Koh Lanta can stop at the Trang islands.
Island-hopping speedboats run mainly in the dry season and timetables change each year. For the southern route, see our Koh Lanta to Koh Lipe guide.
Koh Lanta to Koh Lipe boats
Compare seasonal speedboats on the southern route.
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Where to stay on Koh Ngai
There are only a few resorts on the island, all on or near the main beach, ranging from simple bungalows to comfortable beachfront rooms. There are no shops or ATMs, so bring cash and anything you need. Some resorts reduce services or close in the low season.
Many travellers prefer to stay on Koh Lanta, where there is far more choice of hotels and restaurants, and visit the island on a day trip. Read our where to stay in Koh Lanta guide for areas and picks.
Stay on Koh Lanta
Compare Koh Lanta hotels and resorts, then day-trip to the Trang islands.
Best time to visit
The dry season, roughly November to April, has the calmest sea, the clearest water and the most boat connections. From May to October the southwest monsoon brings more rain and rougher seas; some tours and speedboats are cancelled and a few resorts close. If you visit in the wet season, keep your plans flexible.
Practical tips
- Cash — there are no ATMs on the island.
- Supplies — bring sunscreen, medicine and snacks; resort shops are small.
- Connectivity — mobile data works but can be slow; do not count on fast Wi-Fi.
- National park — parts of the area are protected; follow staff instructions and leave no rubbish.
- Combine — pair the island with Koh Muk, Koh Kradan or a few nights on Koh Lanta.
For official information on the province, see the Tourism Authority of Thailand – Trang.
Koh Ngai vs Koh Muk vs Koh Kradan
The three main Trang islands are close together but feel quite different. Use this comparison to decide which one to stay on, or which to prioritise on a tour.
| Island | Highlights | Feel |
|---|---|---|
| Koh Ngai | Long east-coast beach, easy snorkelling | Very quiet, resort-only |
| Koh Muk | Emerald Cave, small village, sunset beach | Local life, more restaurants |
| Koh Kradan | Clear water, long white beach | Simple and peaceful |
If you want a beach and nothing else, Koh Ngai is the easiest choice. If you want a village with small restaurants and the famous cave on your doorstep, Koh Muk is better. Koh Kradan sits somewhere in between and is often called the prettiest of the group.
Sample plan: three nights in the Trang islands
- Day 1 — boat from Koh Lanta or Pak Meng; afternoon on the beach and sunset drinks.
- Day 2 — snorkel the headlands in the morning, then rest; optional longtail to Koh Kradan in the afternoon.
- Day 3 — longtail trip to the Emerald Cave on Koh Muk at low tide, when the swim through the tunnel is easiest.
- Day 4 — onward boat south to Koh Lipe or back north to Koh Lanta.
Planning note
Book your first and last nights on Koh Ngai before you travel in high season, when the small number of rooms can sell out, and confirm your resort's boat transfer times in advance.
Pack light: a dry bag, reef-safe sunscreen, a torch for evening walks, insect repellent and enough cash for the whole stay.
Koh Ngai: FAQ
Is Koh Ngai in Krabi or Trang?
It belongs to Trang province, although it is very close to Koh Lanta in Krabi province, and most tours to it leave from Koh Lanta.
How long does it take to get to Koh Ngai from Koh Lanta?
About 1 hour by speedboat; longer by longtail boat.
Can you do Koh Ngai as a day trip?
Yes. Most visitors see it on a 4 Islands day tour from Koh Lanta or from Pak Meng in Trang.
Is there an ATM on Koh Ngai?
No. Bring enough cash for your stay.
Is Koh Ngai good for snorkelling?
Yes. Coral and reef fish start close to shore, especially around the headlands at either end of the main beach.
Sources: Tourism Authority of Thailand; InsideSamui editorial research. Boat times are indicative and seasonal. Last updated 13 November 2026.
Photos: Khunkay (CC BY-SA 3.0, Wikimedia Commons); Nik Cyclist from Bangkok, Thailand (CC BY 2.0, Wikimedia Commons); Hanumanix at English Wikipedia (Public domain, Wikimedia Commons); Rittigai (CC BY-SA 3.0, Wikimedia Commons); Marcin Konsek (CC BY-SA 4.0, Wikimedia Commons).
Disclosure: InsideSamui may earn a commission when you book through some of the links on this page, at no extra cost to you. Prices and timetables quoted here were checked on 13 November 2026; they change by season and operator, so confirm when you book.