Not all nine islands have beaches, but the ones that do have pristine and powdery white sand. One of the best beaches is located on Koh Tachai, on the northern end of the park. Swim in Similan's turquoise waters and have a picnic on the beach.

Similan is considered to have the very best diving in all of Thailand. The waters are clear and teeming with sea life, including manta rays and whale sharks. Non-divers can still appreciate the reefs of Similan by snorkeling the shallower reefs.

Diving on the east side features coral reefs with slopes. The west side diving is famous for the giant granite boulders that are to be found under the water. Among the best sites are “East of Eden," a slope featuring a diverse corals; Elephant Head Rock (West Side), though the currents here are known to be a bit tricky; and Richelieu Rock, where whale shark sightings are probable.

While it is possible to cruise around Similan National Park's 11 islands, visitors are only allowed to land on Islands #4 and #8, which have trails and viewpoints. Traveling on a liveaboard yacht allows one to see more of the islands, even when it is not possible to go ashore.

Some of the islands are covered with beautiful tropical jungle. Hikers and trekkers will enjoy taking nature walks to examine the area's special flora and fauna.

Although very stringent restrictions apply, one can witness turtle hatching and the hatchlings' accompanying rush to the sea on Koh Huyong. There is a turtle breeding facility here which is run by the Royal Thai Marines.