Top Dive Sites in the Andaman Sea, Thailand

The Andaman Sea is home to some of the most spectacular diving in Southeast Asia — a true underwater paradise that keeps even the most experienced divers coming back again and again.

We’ve logged over 5,000 dives across Indonesia, the Maldives, the Pacific Islands and the Red Sea. And yet, Thailand’s Andaman Sea consistently holds its own against the world’s most famous dive destinations.

In this guide, we’re breaking down the top dive sites in the Andaman Sea, from remote pinnacles teeming with life to coral gardens so vibrant they’ll stop you mid-kick. We’ll share diver tips, seasonal insights, and insider advice to help you plan the ultimate Thailand dive adventure.

📝 Best Season: The Andaman dive season typically runs from late October to April. Marine parks close from May–October to let the ecosystem recover. Visibility and currents are affected by tides and moon cycles, so plan accordingly.

Before you go, don’t forget to grab our free Andaman Coast Pro Packing Guide — it’s full of the simple hacks and must-have gear that make your dive trip run smoothly.

🪸 5. 8 Mile Rock – The Whale Shark Magnet of Koh Lipe

Located a short speedboat ride from Koh Lipe, 8 Mile Rock is a submerged pinnacle that rises dramatically from the depths — and it’s a magnet for life.

This site is carpeted in soft corals and swarming with schooling fish. Whale sharks are frequent visitors, cruising past the rock to feed in the nutrient-rich currents. It’s advanced diving: strong currents are common, but the reward is unforgettable.

📽️ Watch it here: Ultimate Koh Lipe Diving Guide

🪸 4. Stonehenge – Thailand’s Coral Wonderland

Just a 15-minute longtail ride from Koh Lipe, Stonehenge is one of the most visually striking reefs in Thailand. Named after its series of underwater pinnacles, this site is smothered in electric pink and purple soft corals.

Photographers love the way the light filters through in the late morning, illuminating nudibranchs, shrimp and reef fish hiding among the corals. Currents can pick up, but when they do — the coral comes alive.

📽️ Watch it here: Ultimate Koh Lipe Diving Guide

🐋 3. Koh Tachai – Granite Boulders & Manta Encounters

Part of the Similan itinerary, Koh Tachai is a remote, exhilarating dive site famous for its massive granite boulders, thrilling currents, and manta encounters.

You’ll weave through natural swim-throughs while trevally hunt overhead and, if you’re lucky, mantas glide past in the blue. This site is best for advanced divers due to current strength and depth.

📌 We’ll be covering Koh Tachai in a future video — subscribe to our YouTube channel to catch it when it drops.

🌊 2. Hin Daeng & Hin Muang – The Twin Jewels of the South

Translated as Red Rock and Purple Rock, Hin Daeng and Hin Muang are two submerged pinnacles off Koh Lanta. Together, they form one of Thailand’s most iconic dive experiences.

Covered in vibrant red and purple soft corals, these sites attract huge pelagic visitors — including oceanic manta rays at Hin Daeng’s famous cleaning station. Due to their remote location and depth, these are dives for experienced adventurers.

📽️ Watch it here: Top 5 Things to Do in Koh Lanta and Full Koh Lanta Travel Guide

🐠 1. Richelieu Rock – The Crown Jewel of Thai Diving

This is the site that divers cross continents for. Richelieu Rock sits in the Surin National Park, near the Similan Islands, and is often called the best dive site in Thailand.

From the surface, it’s just a tiny horseshoe-shaped pinnacle. Underwater, it’s a bustling metropolis of life: seahorses, ornate ghost pipefish, frogfish, trevally hunting in packs, swirling barracuda, and — if you’re lucky — whale sharks and oceanic mantas.

We’ve done over 20 dives here, and it never fails to deliver.
👉 Pro tip: Position yourself in “the split” — where current hits the rock — for the best big fish action.

📽️ Watch it here: Richelieu Rock Dive Guide

📝 Bonus Tips – Dive Smart in the Andaman Sea

Day Trips vs Liveaboards
Many divers assume liveaboards are the only way to see the Similans. But experienced divers can target the best sites — Koh Bon, Koh Tachai, Richelieu — via day trips from Khao Lak. We recommend Wetzone Divers for a professional, well-timed operation.
Multiple Dives at Richelieu Rock
Don’t just dive it once. Photographers in particular should plan at least two days here to explore both macro and wide-angle magic.
Low Season Secrets
Sites like 8 Mile Rock and Stonehenge remain accessible year-round. Visit between May–October for uncrowded, incredible dives — just plan around local conditions.
Gear & Insurance
Carry DAN dive insurance and comprehensive travel cover like SafetyWing. Marine parks in Thailand are strictly no gloves, no touch, no reef hooks zones. Respect the reef, and dive responsibly.

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🌏 Conclusion – Dive Thailand Like a Pro

From the purple gardens of Stonehenge to the electrifying currents of Richelieu Rock, the Andaman Sea is a playground for divers who crave adventure, biodiversity, and raw beauty.

It’s a place that continues to inspire us, and we hope it inspires you too.

Before your next trip:
📥 Download our free Andaman Coast Pro Packing Guide to make sure you’re fully prepared.
🎥 Subscribe on YouTube for real dive stories and travel guides.
💬 Got a favourite Thai dive site? Drop it in the comments — we’d love to hear your experiences.

Top Dive Sites in the Andaman Sea, Thailand – Ultimate Diver’s Guide