Koh Samui & Ang Thong

Koh Samui sits in the Gulf of Thailand alongside the Ang Thong National Marine Park, an archipelago of 42 islands with emerald lagoons, limestone karsts, and fringing reefs. Diving here rewards with whale shark encounters from March through May, dense schools of snapper and fusiliers around pinnacles, and macro life tucked into rubble and soft coral gardens. The marine park's protected status keeps reef fish populations robust, and seasonal visibility peaks in the dry months of January through April.