Slip beneath the warm waters surrounding Koh Samui, Thailand, and discover one of the Gulf of Thailand’s most rewarding dive destinations. Diving in Koh Samui attracts scuba divers from around the world thanks to its rich marine biodiversity, calm conditions, and easy access to diverse underwater landscapes.
The island offers an impressive variety of Koh Samui dive sites, including granite pinnacles, rocky seamounts, and colorful coral reefs alive with tropical fish. As you venture to deeper offshore sites, look into the blue for whale sharks, which are regularly sighted in the area. Stingrays, turtles, barracuda, and moray eels are commonly encountered, while black coral, barrel sponges, sea fans, soft corals, and sea anemones create vibrant reef scenes. With such variety and accessibility, scuba diving in Koh Samui remains a top choice for divers exploring Thailand.
Warm seas and consistent conditions make diving in Koh Samui possible throughout the year. Water temperatures remain around 29°C / 84°F, creating comfortable conditions for long, relaxed dives in the Gulf of Thailand.
Divers can enjoy rocky outcrops and coral formations year-round, along with regular sightings of titan triggerfish, sea snakes, and hawksbill turtles. Whale sharks are present across all seasons but are most frequently spotted between April and May, when increased plankton attracts these gentle giants to the deeper pinnacles around Koh Samui.
Underwater visibility can reach up to 30 meters from July to September, offering excellent conditions for reef exploration and macro diving. During these months, photographers and macro enthusiasts search for nudibranchs, shrimp, and other small critters tucked into crevices, rock gaps, and artificial reefs—ideal subjects for underwater photography in Koh Samui.
Located in the Gulf of Thailand, Koh Samui forms part of the Chumphon Archipelago, a chain of more than 600 islands that includes Ang Thong Marine Park, Koh Phangan, and Koh Tao—all well known for excellent scuba diving.
Most travelers heading for diving in Koh Samui arrive via Koh Samui Airport, with frequent connecting flights from Bangkok (around 1 hour 30 minutes) and Phuket (about 1 hour). The airport is also classed as international, offering direct flights from Singapore and Hong Kong, making access easy for overseas divers.
High-speed ferries link Koh Samui with the Thai mainland, while nearby dive hotspots Koh Phangan and Koh Tao can be reached in approximately 30 minutes and 3 hours respectively. Once on the island, getting around is simple using songthaews, taxis, rental cars, motorbikes, or on foot. Songthaews—converted pickup trucks with bench seating—are the most popular and budget-friendly option, and a great way to meet fellow divers while exploring Koh Samui.
Technical Diving
Freediving
Emergency First Response
FREE – Introduction to Scuba Diving Online
Marine Debris
Shark & Ray Protection
Adopt a Dive Site
