The tropical paradise island of Koh Samui is another one of the beautiful diving destinations in the Surat Thani region of Thailand. Located nearby its equally stunning neighbours, Koh Phangan and Koh Tao, this island offers divers and non-divers an exceptional exotic experience both above and below the waves. Imagine white sandy beaches, azure warm water teeming with colorful marine life, surrounded by a backdrop of clear blue skies, brilliant green mountainous fauna, and swaying coconut trees. This is only the start of what Samui will present during your stay. Whether you’re after a quiet, lazy getaway, or to party until the sun comes up, this island will not fall short of your expectations.

The island, often referred to as a diver’s paradise, boasts mostly easy, relaxing dive sites that are suitable for all skill levels, from complete beginners all the way up to the most seasoned of divers. Visibility is often good, and can be anywhere from 3-30 meters. Currents are normally minimal, but can sometimes vary depending on the weather. On the west coast, currents can be strong during the monsoon season.

Scuba diving is easily available at the many accredited dive centers and dive resorts all over the bustling island, and there are also plenty of liveaboard trips that include Koh Samui and its neighbours in their diving trips. Dive courses are also readily available at many of the dive centers and resorts, and are often very reasonably priced as a result of competition. Due to the high numbers of establishments offering dive instruction, it’s easy to find affordable courses in your preferred language. The island itself is perfect to obtain an open water license, thanks to the shallow, calm ocean conditions. 

The majority of dive sites are only a short boat ride from the shore, and these such sites are usually always suitable for novice divers. Many of the island’s dive operators travel to world-class dive sites that are a little further afield and may be more suited to those with more experience, such as those in Ang Thong National Marine Park, and the famous Sail Rock, which is one of the most popular spots in the Gulf of Thailand.

Diving is good all year round on Koh Samui, though it does experience some seasonal differences. Later December to April is the cooler, dry season, and is thought to be the best time to dive when air temperatures aren’t too uncomfortably hot, usually lingering between 27°C-30°C (80°F-86°F). Sea temperatures are also just as warm and tend to fluctuate between the same numbers all year round. Visibility is usually at its clearest, and dive sites tend to experience higher numbers of divers. This period is also the high season, when accommodation and diving may be more expensive than in the low season. 

May to September can experience some showers but normally they’re short and brief. Air and ocean temperatures are still hot, and if you want the best chances to encounter whale sharks, March, April and May are the months to visit. 

March and April are the hottest months when temperatures can often reach into the 40s Celsius (low 100s Fahrenheit). It’s almost non-stop sunshine with no rainfall to break the heat, even at night. 

October and November tend to be rainy months, although some sunny days can occur, and diving is still possible thanks to amazing marine life that remains unchanged throughout the year, and a beautifully warm ocean. What’s more, you’re likely to find great deals on accommodation and diving in this period, due to it being the low tourist season, so why not take advantage?

The diving on and around Koh Samui is typical of what you’d expect from many of Thailand’s tropical dive sites - colorful reef diving, shipwrecks, exciting wall diving with dramatic drop-offs and overhangs, and for experienced divers, cave diving is possible with some sites boasting some impressive topography, including swim-throughs and caverns. Drift diving can also be done, however, it depends on currents on the day, as they are not always guaranteed.

For amazing topography where you can enjoy caves and swim-throughs in addition to vibrant marine life, visit Koh Yippon and Koh Wao in Ang Thong National Marine Park. Green Rock and Southwest Pinnacles also offer fun swim-through and wall diving opportunities. 

Divers hoping for wreck diving can head to the HTMS Sattakut, which is an ex-Thai navy vessel that was sunk to serve as a dive attraction and artificial reef. The vessel is a great spot to undertake a wreck specialty course. It lays on a sandy bottom at around 30 meters and is approximately 49 meters in length and 7 meters wide. 

For amazing reef dives with an abundance of breathtaking marine species, you can be sure to enjoy it all at any of the dive sites in and around Koh Samui, thanks to its perfect location in the tropical Gulf of Thailand.

Divers can encounter a wealth of stunning marine life all around Koh Samui and its neighbouring islands. From macro critters like nudibranch, tiny shrimp, crabs and seahorses, to colorful reef fish and larger creatures like barracuda, sea turtles, sharks and even whale sharks, this magnificent area of the world truly has it all. 

Whale sharks sometimes frequent the deeper sites like Sail Rock, Southwest Pinnacle and Chumphon Pinnacle, especially in March, April and May, so be sure to include these sites on your dive list. At almost all the unforgettable dive sites in the region, expect to see plenty of hard and soft corals and sponges of varying colors, a myriad of anemone fish like clownfish and pink anemonefish, in addition to tons of parrotfish, bannerfish, angelfish, batfish, butterflyfish, damselfish, lionfish, and those who’re the masters of disguise, such as scorpionfish and stonefish. Moray eels, stingrays and lobsters are also fairly common, and schooling fish can also be encountered, including jackfish and barracuda. Hawksbill and green sea turtles aren’t particularly uncommon either, and reef sharks such as the blacktip can be spotted in these waters. 

There are so many incredible sites, including Green Rock, White Rock, Samran Pinnacle and Hin Wong. But mention just a few, we’ll begin with Sail Rock. Situated North of Koh Samui between Koh Tao and Phangan, the world-famous dive site is often referred to as the best dive site in the Gulf of Thailand. Extending 40 meters below the surface, the pinnacle hosts abundant life, and whale sharks are often seen here. Plenty of fish and coral species thrive, including reef fish, anemonefish, and schooling fish like barracuda and snapper.

Chumphon Pinnacle is also said to be one of the best sites in the area, along with Sail Rock. Consisting of four underwater pinnacles, starting at around 14 meters and dropping down to about 36 meters, this site is suitable for advanced divers due to its depth, or divers wanting to undertake deep dive training. Tons of marine life cover the coral encrusted pinnacles, and plenty of fish surround it, such as barracuda, snapper, batfish, groupers, and lots of anemone fish. If you’re lucky, you may even spot a whale shark here. 

North of Koh Samui and southeast of Koh Tao, is a site named Shark Island, which is a small island famed for its abundance of stunning marine life. Sloping down to around 24 meters, the island boasts two dive sites on either side, of which one consists of a myriad of soft and hard corals and sponges, and is where turtles are commonly found. The other side hosts an array of soft corals, among which plenty of critters thrive, including stingrays, eels, pufferfish, sea snakes and triggerfish. Leopard and reef sharks can also be found, and very lucky divers can encounter passing whale sharks. 

The HTMS Sattakut Wreck is frequented by dive operators, and acts as an artificial reef, holding a wealth of life. The maximum depth is about 30 meters, and the top reaches approximately 18 meters. It’s a must for any wreck enthusiasts visiting the area.

Finally, The Southwest Pinnacles are three rock formations that drop to around 30 meters and are a series of wall dives. Tons of colorful coral and sponges cover the pinnacles, and lots of marine critters call this spot home.