Ko Mieng or Ko Si(Four) is the location of the park's HQ. Here are two white powdered beaches, the large Haad yai, in 'front' of the island and the small Haad lek, which is about 20 minutes walk away, through rich evergreen forest, on the other side. It is home to NICO bar Pigeon, Flying Fox, and Hairy-legged Mountain Crab ('Poo Gai' in Thai, because it cheeps like a baby chicken), as well as much other wildlife. Facilities include a freshwater source, bungalow, campsites, a restaurant, a shop and long-tails boat for hire for snorkeling.

Ko Similan or Ko Paed (Eight) is the largest island with a large beautifully curved bay named 'Ao Kuerk'. The beach here is white like powder. Snorkeling is possible from here. To the right is found the towering 'Sailing Rock', a symbol of Ko Similan which can be climbed in order to take in a panoramic view of the bay.

Ko Payu or Ko Jed (Seven) has a very stunning snorkeling and scuba-diving site on the eastern shore. Many divers prefer this site to any other because there are both hard and soft corals, sea fans, and many species of schooling fish. A minor site is found to the west, and another to the north has rocks covered with sea fans, The island has no beach.Pusa Rocks is a small island shaped, above water, like a skull. Underwater are holes and crevices, very exciting for divers.

Ko Haa (five), to the west of the island is a large underwater rock full of soft corals. Nearby, garden Eels can be seen stretching their necks from holes in the sandy floor.

Fantasy Rocks are another scuba-diving site consisting of several large rocks totally covered with soft corals, sea fans, and many species of fish. They are located to the west of Ko Similan (Ko Paed), and are one of the more popular diving sites.

Christmas Point Rocks are another scuba diving site, a complex of rocks full of soft corals and sea fans found to the northwest of Ko Ba-ngu or Ko kao (Nine).
 

Shark Ridge Rocks are pinnacle rocks near Ko Payan or Ko Sam (Three). Here, several species of sharks like Silvertip, Leopard Shark, and Reef White tip can be found.

Ko Bon is located between the Similan Islands and Ko Tachai. There is no beach and the underwater scenery here is not as beautiful as elsewhere, but scuba divers may often find Manta Rays.

Ko Tachai is located at the northernmost tip of the park. There is a beautiful white beach on the island but no accommodation. The water is suitable for scuba diving, and Whale Shark is often found here.