Why the Andaman Sea Is Better for Diving Than the Gulf of Thailand

Andaman Sea

Why the Andaman Sea Is Better for Diving Than the Gulf of Thailand

Thailand is bordered by two major bodies of water: the Andaman Sea on the west and the Gulf of Thailand on the east. Each coastline has its own unique charm, but when it comes to diving—whether snorkeling or scuba diving—the Andaman Sea stands out clearly as the superior destination.

This difference comes from key factors such as geography, water clarity, ocean currents, ecosystem diversity, and the overall underwater landscape, all of which directly influence the diving experience.

1. Superior Water Clarity and Excellent Underwater Visibility

Andaman Sea

• Crystal-clear turquoise water

• Underwater visibility often reaches 20–30 meters on good days

• From November to April, the sea is calm with very low sediment

• Clear water flows in from the Indian Ocean year-round

Gulf of Thailand

• Seabed consists mostly of mud and fine sand

• Sediments are easily stirred up

• Visibility is usually just 5–10 meters in many areas

• Water clarity changes frequently due to shifting winds and currents

High water clarity is one of the most important elements of the diving experience, and the Andaman Sea has a clear advantage.

2. Healthier and More Diverse Coral Reefs

The Andaman Sea is home to abundant coral reefs, both hard corals and soft corals, thanks to stable salinity, ideal water temperatures, and strong sunlight that reaches deep underwater.

Famous coral reef areas in the Andaman Sea

• Similan Islands

• Surin Islands

• Phi Phi Islands

• Koh Lanta

• Koh Lipe

• Tarutao

• Koh Haa

Corals found here include:

• Staghorn coral

• Brain coral

• Soft corals in various colors

• Sea fans (gorgonians)

• Large coral bommies

Gulf of Thailand

While coral reefs do exist, they are generally less diverse and less abundant due to:

• Cloudier water limiting sunlight

• Shallow seabeds where corals are easily damaged

• Environmental pressures from coastal development and human activity

3. Greater Marine Biodiversity

The Andaman Sea lies close to the Indian Ocean, which brings warm currents carrying a wide range of marine species each year.

Common marine life in the Andaman Sea

• Whale sharks

• Manta rays

• Blacktip reef sharks

• Sea turtles

• Octopuses

• Moray eels

• Batfish

• Lionfish

• Multiple species of clownfish

• Large schools of reef fish

Gulf of Thailand

Marine life is present as well, but:

• Fewer species

• Schools of fish are often smaller

• Rare creatures are seldom spotted

This makes the Andaman Sea far more exciting for divers.

4. More Dramatic and Varied Underwater Topography

One of the key strengths of the Andaman Sea is its limestone-based underwater landscape, which creates diverse and visually striking formations.

Features commonly found in the Andaman Sea

• Steep underwater cliffs

• Underwater canyons

• Caverns and swim-throughs

• Shipwrecks

• Massive coral structures

• Deep-water sites for advanced divers

These elements make the diving experience more dynamic, adventurous, and visually impressive.

Gulf of Thailand

• Mostly sandy and flat seabeds

• Simpler underwater structure

• Smaller and more scattered coral formations

The underwater scenery tends to be gentler and less dramatic compared to the Andaman side.

5. Better Opportunities for Underwater Photography

Because the Andaman Sea offers:

• Clear water

• Strong natural light

• Diverse marine species

• Colorful coral landscapes

Underwater photos and videos turn out brighter, sharper, and more vibrant.

Top underwater photography spots include:

• Similan Islands

• Surin Islands

• Koh Lipe

• Phi Phi Islands

By contrast, the Gulf of Thailand often has lower visibility, making photography more challenging.

6. A More Predictable and Well-Defined Diving Season

The Andaman Sea has clear, predictable diving seasons:

• November – April: Best visibility, calm seas, ideal for all types of diving

• May – October: Monsoon season, some national parks close for marine restoration

This helps divers plan trips with confidence.

Gulf of Thailand

Diving is possible year-round, but:

• Visibility varies greatly

• Weather changes quickly

• Conditions are harder to predict

Conclusion

The Andaman Sea is unquestionably better suited for diving than the Gulf of Thailand, thanks to:

• Clearer water

• More vibrant and healthier coral reefs

• Greater marine biodiversity

• More dramatic underwater landscapes

• Superior conditions for underwater photography

• A clearly defined diving season

These factors make the Andaman Sea a world-class diving destination for beginners and experienced divers alike.

For anyone seeking a truly spectacular underwater experience, the Andaman Sea is a place that should be visited at least once in a lifetime.