This private island off the northwest coast of Koh Tao audaciously charges admission to all visitors. Overcrowding used to be a problem thanks to a neverending stream of dive trips but things seem to have dropped off a bit. Ko Tao offers plenty of other gorgeous spots that don't charge for the privilege of a paddle.

Having said that, Koh Nang Yuan is a stunning island formed by three separate rocky outcrops connected by white-sand beach, most of which is submerged at high tide. The view from the southernmost outcrop is particularly impressive.