Best Places to Dive in Thailand: From Koh Tao to Richelieu Rock

• Thailand's scuba diving is divided into the Gulf of Thailand and the Andaman Sea (Andaman Sea, west coast, and the Gulf of Thailand, east coast), which are at their best at different times of the year.
• Dive site closures: There are dive sites that close seasonally. For example, the national parks of Similan and Surin are already seasonally closed during the period of 15th May to 15th October. Always check the current Park updates.
• Richelieu Rock and Hin Daeng/Hin Muang are popular with whale sharks and mantas, as Sail Rock and Chumphon Pinnacle are best suited to intermediate divers.
• Approximate day trips are 3,000-6,000 THB, whereas liveaboards vary depending on the schedule.
• Novices will enjoy learning to dive in the reefs of Koh Tao or Koh Samui, but advanced divers are able to dive deep on a wreck such as the HTMS Chang or King Cruiser Wreck.

Before exploring the sites, it’s important to understand Thailand’s two main diving regions:

• Andaman Sea (Phuket, Krabi, Khao Lak, Koh Lanta):  The best time to visit Thailand in the Andaman Sea is from November to April. Stronger waves and park closures affect the off-season.
• Gulf of Thailand (Koh Tao, Koh Phangan, Koh Samui): Best from May to September, with relatively calm seas when the Andaman is rough. Koh Tao certifies over 100,000 new divers each year, making it one of the most popular training spots worldwide. 

The Ko Phi Phi Islands are among Thailand’s most famous dive destinations, offering vibrant reefs, limestone cliffs, and clear waters. It is a perfect starting point if you’re exploring the nearby best islands in Thailand.

• Highlights: Blacktip reef sharks, turtles, and coral gardens.
• Depth & Skill: 5–25 m; beginner-friendly.
• Season: November–April.
• Price: 3,500–4,500 THB for a two-dive trip.

Often ranked among the best dive sites in the world, Richelieu Rock lies within Mu Ko Surin National Park.

• Highlights: Whale sharks and manta rays (Feb–May).
• Depth & Skill: 10–35 m; advanced divers.
• Season: Mid-Oct to mid-May.
• Price: From 18,000 THB for 3–4 days.

Located off Koh Chang, this Thai Navy ship was deliberately sunk in 2012. It is easily accessible by short boat rides from Koh Chang.

• Highlights: Batfish, groupers, barracuda, night dives.
• Depth & Skill: 5–30 m; Advanced Open Water recommended.
• Season: Year-round.
• Price: 3,500–4,500 THB.

Situated between Koh Tao and Koh Phangan, Sail Rock is famous for its chimney-like swim-through. This is one of the best diving spots in Thailand, which can be covered on day trips from Koh Tao or Koh Phangan.

• Highlights: Barracuda, jackfish, whale sharks.
• Depth & Skill: 5–40 m; intermediate divers.
• Season: Year-round, best May–Sep.
• Price: 3,000–3,800 THB.

Named for the harmless leopard sharks, it is an ideal spot for Open water divers. You can combine this diving spot with top water activities in Thailand at Shark Point with the King Cruiser Wreck.

• Highlights: Soft corals, seahorses, reef fish.
• Depth & Skill: 10–30 m; Open Water divers.
• Season: November–April.
• Price: 3,500–4,500 THB.

A granite formation covered in anemones, perfect for experienced divers. Located just  30–40 minutes from Koh Tao, it is one of the best diving spots in Thailand. 

• Highlights: Barracuda, trevally, whale sharks.
• Depth & Skill: 14–36 m; strong currents.
• Season: Year-round; calmest May–Sep.
• Price: Around 3,000 THB.

King Cruiser Wreck spot is a sunken passenger ferry near Phuket that became an artificial reef. Add this site to your Thailand itinerary to explore maritime history. 

• Highlights: Snappers, scorpionfish, soft corals.
• Depth & Skill: 18–32 m; advanced divers.
• Season: November–April.
• Price: 3,800–4,500 THB.

Located near Koh Lanta, these sites are famous for manta rays and whale sharks.

• Highlights: Manta cleaning stations, whale sharks.
• Depth & Skill: 10–60+ m; advanced divers only.
• Season: November–May.
• Price: From 5,500 THB.

Koh Samui is a great base for exploring Sail Rock and Ang Thong Marine Park.

• Highlights: Beginner reefs, snorkelling, Sail Rock trips.
• Depth & Skill: 5–25 m; great for learners.
• Season: May–September.
• Price: 3,000–3,500 THB.

Koh Bon is a part of Similan National Park and is known for manta sightings. It is mostly accessible from Khao Lak. 

• Highlights: Manta cleaning stations, reef sharks.
• Depth & Skill: 12–40 m; intermediate to advanced divers.
• Season: Mid-Oct to mid-May.
• Price: Day trips ~5,800 THB.

• For beginners: Koh Tao is the cheapest and most popular place to get certified, with Open Water courses starting from 9,000 THB.
• For advanced divers: Plan liveaboards to Similan and Surin Islands for rare pelagic encounters.
• Eco tip: Always choose operators that avoid plastic, provide reef-safe sunscreen advice, and respect marine park rules

With shallow reefs of Koh Tao in the North and dramatic drop-offs of Richelieu Rock in the South, diving spots in Thailand have something to offer every diver. From beginner to advanced divers, they might practice in the sea, where they can learn in calm waters and go in search of whale sharks or visit wrecks. Sip with the Thai island hopping, the discovery of the best temples in Thailand, or the revelry of the nightlife in Thailand to create a memorable travel experience. Be prepared to have a new experience with pickyourtrail. Book your trip hassle-free now! Visit Thailand tour packages at the lowest rates.