Ko Tarutao is the largest island in the archipelago — 152 square kilometres of jungle-covered mountains, mangrove creeks, and empty white-sand beaches. The park headquarters and the only formal accommodation sit on the northern bay of Pante Malacca, a long curve of fine sand backed by casuarinas. The bungalows are basic national-park style; there is a small restaurant, a shop, and bicycle hire, and almost nothing else.
Walking trails run from the headquarters into the interior — short loops through the rainforest and a longer trek up to Toe-Boo Cliff, a viewpoint that opens out over the bay and the surrounding islands. The west and south coasts have more beaches; Ao Sone is a quieter alternative an hour's walk south, and further down at Talo Wao Bay are the overgrown ruins of the wartime prison camp. Wildlife is abundant: macaques and dusky leaf monkeys in the canopy, water monitors on the trails, and hornbills crossing the bays.
Few foreign visitors stay on Tarutao itself, preferring Ko Lipe an hour to the west. That is exactly its appeal. With your own camping kit and a willingness to do without restaurants and bars, you can have stretches of beach and forest to yourself in a way that is no longer possible on most of southern Thailand's coast.