National Parks in or near Phuket:

Sirinat National Park
This park which covers an area of 90 square kilometers is located on the road to the airport, 37 kms from Phuket town. It has long secluded stretch of beautiful beaches, Hat Nai Thon, Hat Nai Yang, Hat Mai Khao and Hat Sai Kaeo, where gigantic sea turtles go ashore to lay their eggs from November to February.
Located within the park:
Mangrove Forest
A forest situated in Sirinat National Park near Ta Chatchai on Phuket's northern tip. Much prized by scientists are the mangroves--saltwater swamps with unique eco-systems. There are many unusual perennial plants to be found here so anyone with an interest in horticulture will be enjoyable. Among the more significant there are; mountain ebony (kong kang bai lek), red cycas (prong daeng), black myrsina (samae dam), the Lady's Nails quisqualis (leb mue nang), and various creepers and climbers. There are also many mangrove-dwelling animals with unique evolutionary characteristics.

Mu Koh Similian National Park
In a area of 50 km of the west coast of Phang-nga in the Andaman Sea, you can find this group of 9 small islands. Because of the great natural beauty found on the islands and because of the extensive surrounding coral gardens beneath the waves it is among one of the loveliest places on Earth. The island also are undeveloped and unspoiled, with a numerous species of fish, crustaceans and other forms of sea-life abound. Water clarity and diving are excellent here.  Similan is corrupted from the Malay Sembilan and means nine.  From north to south in order the islands are : Ko Bon, Ko Ba Ngu, Ko Similan, Ko Pahyoo, Ko Miang (two islands), Ko Pahyan, Ko Payahng  and Ko Hu Yong. 

Mu Koh Surin National Park
This is a group of five islands situated close to the marine boundary between Burma and Thailand in Khuraburi. Because of its distance from the coast it so far has been little visit and it is a protected area. The shallow channel between the two principal islands - about two meters at high tide-has one of the most remarkable panoplies of coral reef life to be found anywhere. Scuba gear is by no means necessary to get a good look at the reefs, a mere snorkel and mask is sufficient. It is making this a perfect destination for those who would like to have the experience of diving but have no time for a scuba course.  Accommodations at the National Park are Spartan, but the modest inconvenience of roughing it will be amply rewarded by the experience supplied.

Ao Phang Nga National Park
A national Park in the districtsof Phang-Nga Town and Takua Thung with a total area of 250,000 rai (1 rai = 1,600 sq. meters).  Phang-Nga Bay's bizarre landscape, which includes more than 120 singularly strange looking islands get a lot of visitors coming here for viewing.  There are many places where boats can be rented to travel to Phang-Nga Bay, where you also can see the famous James Bond Island.

Khao Lamphi National Park
This national park, also called Hat Thai Muang National Park in Thai covers a total area of 45,000 rai. Khao Lamphi is a phrase indicating the end of the mining district, and indeed this area was formerly, from ancient time to modern, one of the great repositories of in the world. Mining has ceased, and little trace remains to the untrained eyes except in the name.

Phi Phi National Park
Hat Noppharat Thara-Ko Phi Phi National Park is situated very near Krabi. The Park contains extensive mainland beaches, over 80 lesser islands, and two islands of outstanding physical yet contrasting beauty which epitomizes everyone's ideal of the perfect tropical island.

Sourced from: Sawadee.com