© iStock/ppnmm Diving the Western Gulf Islands From Koh Tao to Koh Phangan and Koh Samui, the islands of the Western Gulf of Thailand offer wonderful diving conditions, with vibrant reefs and the chance to spot whale sharks. Koh Samui is the most popular island and a great base to combine diving with a beach holiday. Most of your dives will involve boat trips out to Koh Phangan and Koh Tao, part of the 600-island Chumphon Archipelago. At the former you can spot whale sharks between March and April and dive at one of the best sites in the Gulf of Thailand, Sail Rock. A 15-minute boat ride from the beautiful Koh Phangan, this part-submerged rock pinnacle is home to everything from the tiniest macro critters to batfish and even bull sharks. For its part Koh Tao promises dramatic rock pinnacles blanketed in coral, wrecks and reefs busy with colourful marine life. A paradise island with swaying palms, sweeping beaches of brilliant white and dramatic cliffs, its underwater delights are just as plentiful. The Chumphon Pinnacle is known as one of the best dive sites in Thailand, thanks to its amazing rock formations, where giant barracuda, grouper and snapper shelter. Diving around these islands promises hard and soft coral, wrecks and clear, warm waters, although monsoon weather means it is best to avoid November. Generally, the water temperature is between 28 and 30C (82-86F) with around 20m (65ft) visibility. Featured places to go in Western Gulf Islands © AqualungKoh SamuiExpect excellent, well-organised diving on Koh Samui with some beautiful shore dives where you can see whale sharks, turtles and schooling fish.Learn more © MaresKoh PhanganKoh Phangan enjoys a fantastic location for access to some of the West Gulf’s best dive sites.Learn more © ScubaproKoh TaoThere is something for everyone on Koh Tao, one of the best dive sites in Thailand with reefs, wrecks and vast rocky pinnacles.Learn more © ScubaproKoh NangyaunThis unique island, actually three separate islands connected by a beach, Koh Nangyuan has four beautiful dive sites with some interesting underwater topographyLearn more Dive Sites in Western Gulf Islands Discover the wonders of the deep with SSI's blog Join us on an exciting journey of discovery and learn more about exhilarating diving adventures, dedicated conservation initiatives, and innovative educational opportunities that will help you illuminate the extraordinary beauty of the underwater world. Let's explore the underwater world together and delve into the hidden wonders beneath the gentle waves.