Gulf of Thailand
Cambodian and Thai islands in warm, shallow, seasonal water.
4 records across Cambodia and Thailand, and the smallest regional presence for the biggest tourist coastline. That gap is the story: Thailand has thousands of islands and almost none held by a single property, because the land tenure and the development pattern never allowed it.
The two Cambodian entries were both built by founders rather than groups, and both put conservation before rooms: Song Saa created the country's first marine reserve, and Krabey's jungle plan came from an island with almost no sand. Cape Fahn is the Thai exception, a private island within sight of Koh Samui, selling proximity rather than isolation.
The water is the honest limitation. Warm, shallow, seasonal, often clouded — this gulf does not offer the clarity of the Andaman side, and the register does not pretend otherwise.