4 Islands, Emerald Cave and Koh Kradan Longtail Tour Koh Lanta

Old Town Pier and the longtail journey south

The day begins on the east coast of Koh Lanta Yai at Old Town Pier, beside the lobster monument at the edge of Lanta Old Town, where wooden stilt houses and old shophouses line the water. Our driver brings you here from your hotel, and the crew welcomes you aboard a longtail, the narrow wooden boat with a long-shafted engine that is a symbol of southern Thailand.

From the pier, the boat heads south into the Andaman Sea towards the islands of Trang province, a journey of about an hour and a half. The engine is loud and the sea can be lively, but the views of limestone islands rising from turquoise water are spectacular. Many visitors wonder how to get to the Trang islands from Koh Lanta: this longtail route is the easiest way to see four of them in a single day.

Koh Chueak: the first snorkelling stop

Koh Chueak is a small rocky island near Koh Muk, its steep limestone walls dropping straight into the sea. Around its base lies a shallow reef with soft corals, sea fans and swarms of tropical fish such as sergeant majors, parrotfish and butterflyfish, which makes it one of the best snorkelling spots in the area for beginners.

The boat anchors close to the rocks, and you have about 40 minutes in the water with the snorkel mask and life jacket provided. Your guide points out the best areas and keeps an eye on swimmers. The water here is usually clearest in the morning, before the tide changes, so this early stop is often the favourite of keen snorkellers. Do not touch or stand on the corals, which grow very slowly and are easily damaged.

The Emerald Cave on Koh Muk

The highlight of the day is the Emerald Cave, known in Thai as Tham Morakot, on the west coast of Koh Muk. At its entrance, the sea flows into a tunnel about 80 metres long through the limestone cliff. Led by your guide, you swim through the darkness with the light of headlamps, following a rope line, until a glow of green light appears ahead.

You then emerge into a hidden lagoon: a small white-sand beach enclosed by towering cliffs covered in jungle, with only a circle of sky above. Local legends say pirates once hid their treasure here. Is the Emerald Cave worth visiting? For most guests it is the most memorable moment of the trip. Entry depends on the tide and waves, so your guide checks conditions at the entrance before the group swims in; life jackets are worn throughout.

Koh Ngai: beach lunch and swimming

Next, the longtail continues to Koh Ngai, a hilly island covered in tropical forest, with a long beach of soft sand on its eastern shore facing the limestone peaks of the mainland. The water is calm, shallow and turquoise, perfect for a swim after the cave.

Lunch is served right on the beach as an all-you-can-eat buffet of Thai dishes, with vegetarian and halal choices; let us know your needs when booking. You have about an hour and a half here to eat, swim, snorkel near the rocks at the end of the beach or simply rest in the shade of the trees. It is a relaxed break in the middle of a full day, and one of the most beautiful lunch settings on any Koh Lanta island tour.

Koh Kradan: the white beach to end the day

The default option ends the day at Koh Kradan, part of the Hat Chao Mai National Park, famous for a long beach of fine white sand and water so clear you can see the coral from the shore. Behind the beach, coconut palms and forest cover the island, and the view across the sea to Koh Muk and the mainland is postcard-perfect.

You have about 40 minutes to swim, take photos and sunbathe before the longtail heads back to Old Town Pier, arriving around a quarter to four. Guests who prefer more time underwater can choose the option with an extra snorkelling stop at the Koh Ma reef instead. The best time to visit Koh Kradan and the Trang islands is from November to April, when the Andaman Sea is calmest and the water clearest.