The hook
Thailand's far-eastern islands, almost at the Cambodian border: white sand and genuinely clear water with no full-moon parties, no strip of bars, and, on Koh Mak, a local agreement to keep development low-rise and quiet.
01Why it's worth it
These are the islands Thais point to when they're tired of what happened to Phi Phi and Koh Phangan. Koh Kood (Ko Kut) is the larger and more dramatic, hilly and forested, with jungle waterfalls you can swim under, coconut plantations, a handful of fishing villages, and beaches, Klong Chao, Ao Tapao, that stay close to empty even in season. Koh Mak next door is flat, small, and deliberately low-key: privately owned by a few families who have kept out high-rise resorts and jet skis, with a bicycle-and-scooter pace and shallow, warm water. Neither has nightlife worth the name, which is the point. The trade-offs are real: getting there takes a full travel day from Bangkok via Trat, prices are higher than the mainland because everything is shipped in, and in the May–October monsoon many places shut entirely.
02How to experience it
Fly or bus to Trat, then ferry out, and give each island several days rather than hopping. Rent a scooter or kayak, find the waterfalls on Koh Kood, snorkel the reefs off Koh Mak, and accept that dinner will be at your bungalow. Come between November and April, and book ahead in peak weeks since capacity is genuinely small.
From the locals
Thais recommending them do it with a note of reluctance that says everything: "we Thais wish to keep this island group fairly secret," one wrote, before giving it away anyway, "Koh Kood, the island next to it, is even more beautiful."