Koh Racha Yai lies in the Andaman Sea south of Phuket and is one of the more accessible offshore destinations in the region, reached by day boat from Rawai or Karon. The island offers a wide range of site types across nine recorded sites, including coral reef slopes, walls, sandy bottoms, wrecks, and artificial structures. Depths span from very shallow to around thirty-five metres, covering all skill levels from beginners to advanced divers. Sheltered bays make the island a common venue for training and check-out dives, while deeper sites such as Marlas Mystery Wreck suit more experienced divers. Recorded species include sea kraits, giant moray eels, pharaoh cuttlefish, nudibranch, peacock mantis shrimp, and reef stonefish.
Monthly water temperature across Koh Racha Yai's sites, from satellite sea-surface data corrected for depth. The band shows the site-to-site spread.
Water temperature remains consistently warm throughout the year, with the warmest period in late spring. The Andaman Sea season broadly favours diving from October through May, and visibility at Racha Yai varies widely across sites and seasons.
20 operators
Rawai, Thailand
Rawai, Thailand
Ban Karon, Thailand
Water temperature around Koh Racha Yai ranges from about 29°C in January to 31°C in May, 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 Racha Yai year-round.
Fin maps 9 sites in Koh Racha Yai (9 scuba diving sites and 5 snorkelling spots, with some suited to both).
Across Koh Racha Yai's dive sites, April and November are most often reported as the best months to visit.
1 more site to explore
