About 100 Degrees East
100 Degrees East is an award-winning marine tour operator based in Bophut on Koh Samui, specialising in small-group snorkelling and diving excursions throughout the Gulf of Thailand. Founded with a commitment to ocean conservation, they became Koh Samui's first plastic-free marine tour operator, eliminating single-use plastics from every trip and running regular reef clean-up dives.
Their tour roster includes full-day excursions to Ang Thong National Marine Park, Koh Tao, and Koh Phangan, as well as private charter options to custom destinations. Every trip caps at 12 adults — or 14 guests when children aged four to twelve are included — ensuring personal attention from the experienced marine team. Snorkelling gear, fins in all sizes, in-water guides, lifejackets, and a home-cooked beach lunch catering to all dietary requirements are included in every tour price.
The operation earned the TripAdvisor Travelers' Choice Best of the Best award, ranking seventh among all experiences in Thailand. Their PADI-affiliated dive team also offers introductory and certified diver excursions to sites like Sail Rock, where whale shark sightings are a regular highlight during season.
