Koh Chang's underwater landscape is built around coral reef diving, with the majority of sites concentrated in the Koh Rang sub-area and a smaller cluster among the Near Islands. Most sites suit beginners, though pinnacle dives at Hin ao yai and Hin Gra Dueng offer more challenge for intermediate divers, and the Pak-1 wreck demands advanced skills. The reef character is consistent: coral gardens, rocky topography, and occasional muck diving at Ko Rang. Pink Skunk Clownfish, Rabbitfish, and Scissortail Sergeant are encountered across virtually every site, while Bluespotted Fantail Ray and Whale Shark appearances add notable highlights. The best conditions fall between November and April, with the wet season bringing a sharp drop in dive activity.
Monthly water temperature across Koh Chang's sites, from satellite sea-surface data corrected for depth. The band shows the site-to-site spread.
Water temperature stays warm throughout the year, barely shifting between the cooler months of January, February and December and the warmer peak around April and May. The best-months data points strongly to November through April as the prime diving window, with conditions deteriorating markedly from June through September. Visibility is variable, so the dry season months reward divers with the most reliable conditions across Koh Chang's reef and pinnacle sites.
28 operators
18 more sites to explore
2 areas
Water temperature around Koh Chang ranges from about 29°C in January to 31°C in April, based on satellite sea-temperature data for its dive sites.
With water around 29–31°C, a rash guard or 3mm shorty works in Koh Chang year-round.
Fin maps 37 sites in Koh Chang (37 scuba diving sites and 12 snorkelling spots, with some suited to both), organised into 2 areas.
The reefs host a rich mix of reef fish observed across nearly all sites, including Pink Skunk Clownfish, Blue-barred Parrotfish, Eightband Butterflyfish, Moon Wrasse, and Rabbitfish. Bluespotted Fantail Ray and Bluestreak Cleaner Wrasse are also regularly recorded. Whale Shark sightings are occasional rather than guaranteed, but they are a documented part of the Koh Chang species list.
The majority of sites across both the Koh Rang sub-area and the Near Islands are rated for beginners, with shallow coral gardens and mild currents at sites such as Banana Bay, Ao Kluai, and Soneva Reef. Intermediate divers can step up to the submerged pinnacles at Hin ao yai and Hin Gra Dueng. The Pak-1 wreck is the only site requiring advanced certification, sitting at significant depth with careful gas management needed.
Koh Rang holds the larger share of Koh Chang's dive sites and offers the widest variety of reef topography, including coral gardens, walls, caves, and pinnacles. The Near Islands cluster is smaller but notable for its wreck diving: Hin Raab combines reef, wreck, and artificial reef structures, while the T11 wreck offers an accessible introduction to wreck diving for beginners. Both sub-areas are reached by boat.
Almost all sites across Koh Chang require a boat to reach, which is the standard mode of access for both diving and snorkelling. A handful of sites, including Ao Kluai and Ao Tum, also permit shore entry, giving divers some flexibility. Operators including BB Divers, Koh Mak Divers, and Good Snorkeling are among those running trips from the area.
