Koh Samui & Ang Thong

Koh Samui sits in the western Gulf of Thailand, a large island with an established resort infrastructure, its own airport, and a cruising ground that extends north to the Ang Thong National Marine Park — a cluster of 42 limestone islands that forms one of Thailand's most visually striking protected areas. The charter market on Samui is smaller than Phuket's but growing. A few operators base their fleets at marinas on the island's north coast, and skippered charters are the common format. The Gulf of Thailand's weather follows a different monsoon pattern from the Andaman Sea: the best months are January through August, with the wettest period in October through December, when the north-east monsoon brings rain and rough conditions to the Gulf coast. Ang Thong Marine Park, roughly 30 kilometres north-west of Samui, is the primary destination. The park's islands are uninhabited, composed of limestone draped in jungle, with sea caves, interior lagoons, and viewpoints reached by steep trails. The anchorages within the park are limited and the park authority controls access — overnight mooring is available at designated spots with a park entry fee. The emerald lagoon on Koh Mae Ko, enclosed by cliffs and connected to the sea by an underground passage, is the park's signature sight. Koh Phangan, Samui's northern neighbour, provides a contrasting stop. The island is best known for its Full Moon Party at Haad Rin, but the north and west coasts offer quieter bays — Chaloklum, Thong Nai Pan — where the pace is gentler and the beach restaurants serve grilled fish to a smaller audience. Koh Tao, further north, is Thailand's diving capital, with a compact island surrounded by coral reef and a concentration of dive operations. Wind in the Gulf of Thailand is lighter and less consistent than on the Andaman coast. Sailing is often motorsailing, with the breeze providing a pleasant supplement to the engine rather than the primary propulsion. The calm water makes this well-suited to families and those who prioritise swimming and shore excursions. Provisioning on Samui is good — the island has supermarkets, fresh markets, and an extensive restaurant scene. Fuel and water are available at the marinas. The Ang Thong islands have no facilities.