We visited Thailand in the spring of 2010 and spent 3 days at the Mo Ko Surin National Park. This park includes a group of islands about 60 km from Ko Lak. There is tent camping and cabins.
The island is beautiful. There are 2 campgrounds from which you can swim and snorkel directly from, or take longtail boat rides to numerous snorkelling spots. There are miles of deserted beaches that are accessible from the island's nature trail. And there are some additional surprises if you take the time to discover them.
Of the 2 campsites, the names of which I don't recall, the one that we didn't stay at was far more beautiful. We stayed at the main campsite, which provided far more tents, and was visited by day travellers, thus it was more crowded and somewhat overun and littered.
I would recommend going with a dive company in Ko Lak. We went with Wicked Diving. They were very professional, organized, and friendly. There are various others in the center of Ko Lak.
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