The Complete Guide to Koh Samui Diving

As you sink into the warm, crystalline waters surrounding Koh Samui, you’ll know that you’ve found a piece of aquatic paradise. The waters of the Gulf of Thailand are teeming with tropical marine life, and divers from all over the world come here to experience this underwater wonderland.

Lying off the east coast of the mainland, Koh Samui is Thailand’s second largest island, renowned for its palm-fringed beaches and mountainous rainforests. But if you prefer getting your action underwater, Koh Samui offers a tempting range of dive sites. If you love exploring towering undersea pinnacles and vibrant reefs, and encountering majestic marine life, then Koh Samui scuba diving is calling you.

And you don’t need to be an experienced diver to enjoy hovering suspended above walls of coral amongst passing parades of fish. In fact, Koh Samui is a perfect place to learn to scuba dive, with one of the many available courses. For those with experience, a Koh Samui diving package may be just the thing for that Thailand holiday you’ve always wanted to take.

Dive sites

There are numerous sites to dive around Koh Samui. Here are some of the best:

Sail Rock

This internationally-renowned site is located north of Samui, between the islands of Koh Tao and Koh Phangan. The granite pinnacle extends 15 metres above the water, but the excitement all happens underneath, where it plunges to the sand 30 metres below. It’s an ideal site for divers of all levels, with something to see from the surface to the sea floor.

Sail Rock’s most famous feature is the “chimney”—a vertical swim-through that is entered at 18 metres and can be exited at 12 or 7 metres into gardens of pink anemones. With few other pinnacles nearby, Sail Rock is a magnet for marine life, with whale sharks being one of the main attractions.  The coral-crusted pinnacle is also home to a myriad of reef-dwelling fish, like angelfish, butterfly fish and scorpion fish. The currents bring schools of pelagics including barracuda, tuna, king mackerel and trevally.

Sail Rock is usually dived in a circular fashion, starting deep and spiralling towards the surface. There can be strong currents around the rock, in which case the local divemasters will guide divers to more sheltered areas. Advanced divers may be able to explore a series of submerged pinnacles off the main rock, which are home to reef sharks.

About 2500 to 2800 baht will buy you a day trip to Sail Rock, including two dives, equipment, an experienced divemaster, lunch and refreshments.

Ang Thong Marine Park

Offering some of the most stunning diving in Thailand, the Ang Thong Marine Park lies roughly 30 kilometres northwest of Samui. The park is a protected area of more than 100 square kilometres. Comprised of numerous limestone islands, Ang Thong boasts underwater scenery to float any divers’ boat, such as caves, swim throughs, overhangs and sloping reefs.

The underwater topography is complemented by an incredible diversity of soft corals, black corals, barrel sponges, sea fans and anemones. Add to this the various fish species— large snappers, banded sea snakes, blue-spotted sting rays, fusiliers and yellowtail barracuda, not to mention the reef fish—and you’ve got a top day’s diving.

Koh Wao and Koh Yippon are two of the most popular sites, with their shallow caves and swim-throughs, housing scores of fish. The mild currents and shallow depth (maximum 20 metres) make this region ideal for new divers.

The Ang Thong Marine Park is accessible by boat for day trips from Koh Samui. Visibility averages 15 metres or more. Day trips including, equipment, breakfast and lunch cost around 2950 baht for two dives, and 3650 for three dives.

Shark Island

Almost directly north of Koh Samui lies Koh Tao, a much smaller island.  Just southeast of Koh Tao, Shark Island is a small uninhabited island named for its resemblance to a shark’s dorsal fin. Shark Island is best known for its diversity of marine life. Sloping gently from the surface down to 24m, each side of the island is a separate dive site— one side has a vast variety of hard corals and sponges, and is a popular home for turtles. The other side boasts some of the most spectacular soft corals you’ll see diving in Thailand, with frequent sightings of stingrays, moray eels, pufferfish, porcupine fish and titan triggerfish.

Divers might also encounter sea snakes, whale sharks, leopard sharks and reef sharks on the deeper side. Lovers of marine critters will also find their bliss here, with nudibranchs and crustaceans amongst the macro-life.

Currents at this site can be stronger than usual, making it perfect for drift diving. Trips from Koh Tao are available for 1000 baht per dive (including equipment and dive guide), with cheaper options for multiple dive packages.

South-West Pinnacle

About 35 minutes south-west of Koh Tao, this site is not to be missed on your Thailand diving holiday. It boasts a series of seven pinnacles, resembling a subaquatic mountain range, with a maximum depth of 30 metres, rising to within 5 metres of the surface.

The main pinnacle is completely carpeted with magnificent pink, blue and green anemones, with their resident anemone fish. You’ll see scorpion fish, dancing shrimps, crabs and groupers. Marine life also includes snappers, emperor, blue-spotted ribbontail rays, white-eyed moray eels and harlequin sweetlips. Giant grouper dwell in the depths, with leopard sharks and whale sharks also visiting the site. King mackerel, tuna and trevally are regulars.

This site can be a bit more challenging than other Koh Tao dives, due to environmental conditions such as currents and waves. Trips from Koh Tao are available for the same prices as above.

HTMS Sattakut – Wreck Dive

Yes, there’s even an option here for the wreck die-hards. The HTMS Sattakut is an ex-Thai navy boat, donated to Koh Tao by a consortium including The Department of Marine and Coastal Resources and the Royal Thai Navy. After being stripped and cleaned, it was scuttled on June 18, 2011.

It now rests in the sand, with the stern lying in around 30 metres of water, the bow in 26 meters, and the bridge at 18 metres. The wreck—which is 49 metres long and 7 metres wide with two canons—has already accumulated an abundance of marine life.  From the portholes on either side, divers can see giant groupers, one-spotted snappers, sweetlips and butterfly fish who have made a home inside.

For PADI Wreck Specialty certified divers, there are two penetration points: one under the gun platform, which leads down the stairs and into the front cabin at around 24 metres; the other at 27metres, leading through a narrow corridor and into the ‘Big room’ at the heart of the wreck.

Between the sand and the bottom of the ship, look around for Jenkins whiprays and blue-spotted ribbontail rays.

A 15- to 20-minute boat ride from Koh Tao, HTMS Sattakut is suitable for divers with advanced certification or higher, with Wreck Specialist certification required for penetration.

Chumphon Pinnacle

Chumphon Pinnacle is located 11 kilometres to the northwest of Koh Tao, and is known as one of the best dive sites in the region. It consists of one enormous coral-covered granite pinnacle, and several smaller ones. The main pinnacle rises to within 14 metres of the surface, and drops away to over 36 metres.

This site is home to plentiful marine life, including batfish, giant grouper, tuna, trevally and schools of barracuda and snapper. Plateaus on the pinnacle are carpeted with brightly-coloured anemones, branching corals, sea whips and barrel sponges. Seasonally, whale sharks and manta rays also pass through the area.

Visibility averages 20 to 30 metres. There can be mild to string currents here, which, combined with the depth, make this dive suitable for intermediate to advanced divers. Double boat dive trips will cost around 2000 baht.

Trips you may like

16-Day Divine Thai Culture

Take a journey from the thriving capital city of Bangkok to the south of Thailand on this city and islands tour!Over 14 days, you’ll explore the capital on boat and tuk-tuk before travelling south to Phuket where you’ll go island hopping and visit an elephant sanctuary. Moving on, you’ll spend a few days in Krabi launching off to explore the islands nearby and finally, you’ll make your way to Khao Lak before returning to Bangkok. For those looking for a relaxing island hopping trip with plenty of adventure and marvellous scenery, then this holiday to Thailand is for you!

5.080 views

from USD 2,453

View

11-Day Authentic South Thailand

Discover the beauty of Thailand’s rich culture, warm and friendly locals and fascinating history and architecture on this nine-day adventure from Bangkok to Chiang Mai!Beginning in Bangkok, you’ll explore the city in a number of unique ways: canal boat, tuk-tuk and a segway scooter! You’ll discover the wonderful landmarks of this city and get your first introduction to Thai food. Moving on, you’ll head to the ancient capital of Ayutthaya to explore the many temples. Next, you’ll head to Sukhothai, Suphanburi and Lampang for a few days before heading north to Chiang Mai where you’ll spend the last few days of your trip exploring the city.

4.8218 views

from USD 2,757

View

9-Day Temples of Thailand

This 7 day Thailand itinerary takes you back in time on a route paved by kingdom builders to learn about the heritage. Thailand’s history is comprised of the rise and fall of kingdoms and on our journey, we’ll cycle through more than 700 years of history, visiting three UNESCO World Heritage sites that defined the country and culture of Thailand. The Chakri dynasty established the current capital of Bangkok or, as known by locals, Krung Thep, our starting point. From here we head north to the former Kingdom of Ayutthaya, once one of the wealthiest cities in the East. Riding north through the rice basket of Thailand, we arrive at what is considered to be the first true Thai kingdom, Sukhothai. Under the Phra Ruang dynasty, the Thai alphabet was created and Theravada Buddhism was established as the religion in the short 130 years of power. Riding further northward, the terrain becomes more rugged as mountains flank our path on both sides as we enter what was once known as the Lanna Kingdom. Here we’ll cycle through the land once ruled by the Tai people and see their influence in the recently excavated ruins of the Haripunchai Kingdom before arriving at the northern capital of Chiang Mai founded in 1298.Cycling distance: 263 kmBike: hybrid bikeDifficulty: activeThis cycling adventure is for those who wish to see Thailand’s rural countryside and explore the rich history of Siam, all while enjoying an active holiday. The scenery is ever-changing as we start our ride through the emerald paddy fields of central Thailand where the roads are mainly flat, then continue with some undulating terrain and a few gentle climbs in the northern hills, before arriving in the cultural city of Chiang Mai. The trip is fully supported and your guide’s expert knowledge of the area and terrain means that you always know what is coming up in terms of distance and difficulty. This makes a tremendous difference, as does the constant supply of cold drinks and fresh fruit.

4.0113 views

from USD 2,458

View

7-Day Thailand By Bicycle

With Bangkok as your base, this culturally immersive Thai experience takes you on and off the tourist trail in search of temples, markets and rural countryside landscapes finishing on a stunning island!Starting in the capital, you’ll find yourself on all manner of transportation to explore fully. You’ll take a traditional boat through the city’s ‘klongs’, hop on tuk-tuk’s, and metro systems to see temples, the Royal Palace and the depths of Chinatown, Bangkok’s food haven. Leaving the city behind you head to Kanchanaburi, home to the Death Railway before you hop between Siam’s old capitals, Ayutthaya, Lopburi and the famous Sukhothai, the home of Thai culture as we know it today. Each of the capitals have their own tales to tell, taking you on a journey through Thai history that is essential for your cultural immersion, ready to head to Thailand’s most traditional city, Chiang Mai. Your two weeks spent Thailand sightseeing finishes with 6 glorious days to relax and enjoy nature at its finest. You’ll be just moments away from the jungle and beach at all times where you can relax, read a book, go snorkelling, scuba diving or island hopping at your leisure – bliss!

4.8256 views

from USD 1,695

View

14-Day Island Hopping in Thailand

The pristine beaches and stunning limestone scenery of southern Thailand have made it a favourite backdrop for Hollywood movies, such as “The Beach” and of course James Bond’s “Man with the Golden Gun” – you’ll feel like you are on a movie set riding through this gorgeous landscape. Staying at some of the most beautiful resorts Southern Thailand has to offer, including the Haven Khao Lak for some rest and relaxation during your 11-day bike tour!Southern Thailand has more to offer than turquoise waters, white sand and lush jungles – it’s also home to a fascinating mixture of cultures. Thai Buddhists mingle with Muslim seafarers to produce colourful people steeped in history and tradition. Priding themselves on their openness and hospitality, the people of the south, or Khon Dai, are always ready to show “farang” (foreigners) their country.Our tour starts on the Gulf of Thailand, at a pristine beach that is off the tourist track. We then head inland and spend time on a stunning lake and ride on the edge of Khao Sok National Park – home to the last of Thailand’s great rainforests – before we head to the beaches on the Andaman Sea. From Khao Lak, we’ll head to the paradise island of Koh Yao Noi where you’ll spend time with a local fishing family. As we boat through Phang Nga Bay towards Krabi be awed by the spectacular limestone cliffs rising vertically from the sea.Though we ride through the world-class tourist destinations of Khao Lak and Krabi, we also leave behind the tourist enclaves and see a southern Thailand that is a rarely visited gem to be discovered.Cycling distance: 384 km (4 full/4 half)Elevation profile: +3,454m/-3,434mMinimum age: 18 yearsWe cycle 384 kilometres exploring beaches, waterfalls, jungle, fishing villages and islands. We enjoy some time off the bike so we can take in boat rides, wildlife and the culture of this fascinating region. Cycling is on a mixture of tarmac and dirt roads. An air-conditioned minivan that travels behind the group provides excellent support. You can cycle as much or as little as you like and still enjoy the same views as the rest. – Suitability: The riding is primarily on tarmac roads, with a few undulations, but there are no major hill climbs. The distances are well within the capability of most riders with a reasonable fitness level.

4.0375 views

from USD 2,715

View

Diving schools

If all this has whetted your appetite for some underwater action on your Thailand holiday, Koh Samui is the ideal place to gain your dive certification. Its warm water and calm coastline lend themselves beautifully to getting the skills you need to start your undersea adventures.

Accredited dive courses are available through the many dive shops, at very reasonable prices.

Dive operators are located at all the main beach resorts, offering everything from one day courses that give you a taste of Koh Samui diving, right through to instructor level training.  PADI is the most common diving certification agency on Koh Samui, with a few dive centres also offering certification from other agencies such as CMAS, SSI, and NAUI.

The low down on going under

Visibility

Conditions in the Gulf of Thailand mean that you can enjoy diving in Koh Samui all year round. Optimum conditions occur between April and September, with visibility reaching up to 35 metres.

Between October and November, monsoonal winds and swells are rarely severe enough to interfere with diving trips, but can reduce visibility and make boat rides a bit bumpier. From November and February, rain and wind from the northeast monsoon can affect the Gulf, causing waves and a drop in visibility to 10m, so it’s not the ideal time for your Koh Samui diving holiday.

Water temperature

Water temperature ranges from 27 to 30° Celsius—heaven for divers who usually have to squeeze into 5 or 7mm neoprene—with the coolest temperatures between October and December. The coolest time of the year is also the best time to see sharks, because they prefer cooler water.

Whale sharks are the exception—they mainly visit between March and April, and again in September and October.

Climate

Koh Samui sits in the tropics, with a year-round hot and humid climate. Air temperatures usually range between 30 and 35°C. March and April are the hottest months, with average temperatures of 34°C and 75% humidity.

July and August are the busiest months, and the most expensive for accommodation. The rainy season occurs between November and January, with November usually the wettest and windiest month.

Dive trip options

Daytrip boat dives are the most common Koh Samui diving package option. Prices will often include hotel transfers, breakfast, lunch, drinking water, dives, weights and weight-belts, tanks, a professionally qualified divemaster, and taxes.

Some trips will include all dive gear, or offer rental for a small extra fee. Of course, you can supply your own equipment if you are travelling with it. Dive insurance will usually cost extra.

Safety

Sunburn and dehydration are the most common injuries suffered diving in Koh Samui. The sun can be very strong, so be sure to use sun safety principles—stay in the shade (many boats will have a shaded canopy), wear a hat and UV protective clothing, and apply sunscreen liberally and frequently. Nothing can ruin diving holidays faster than burned, raw skin.

Drink plenty of water to avoid dehydration, and steer clear of excessive alcohol the night before a dive. You’ll appreciate the unique underwater experience better without a hangover, and avoid any embarrassment at having to puke through your regulator. Trip operators reserve the right to refuse anyone they feel is unfit to dive.

Should the worst happen, there is a recompression chamber on Koh Samui. The chamber facility also offers free tours, medical advice and dive safety tips.

Travel Info

Thailand has two international airports – Suvarnabhumi Airport in Bangkok and Phuket International Airport. Daily flights are available to Koh Samui from both.

Alternatively, catch a night train from Bangkok to Surat Thani, and transfer to the ferry port for Samui. The standard ferry takes 2½ hours; there is a slow night ferry; and a couple of faster boats. Trains are often full, so book well in advance. The cheapest option is bus transport, but some are more comfortable than others, so check out what you’re paying for. The bus trip takes about 10 hours from Bangkok to Surat Thani.

Thai is the official language, with English widely spoken in tourist areas. Currency is the Thai baht. Credit cards are accepted in most areas.

Shacking up

Koh Samui has a variety of accommodation options, ranging from luxury beach resorts to budget guesthouses.  Some places will offer diving packages that include diving, drinks, lunch and boat-hotel transfers.

Electricity is 22O volts, 50Hz; and internet is common in cities and resort areas.

The combination of spectacular underwater scenery and abundant marine life, combined with the topside beauty, mean a Koh Samui diving holiday is one you’ll be bragging about for years to come.