Wildlife protection
Islands 1, 2, and 3 are closed for public due for turtle hatching protection program and reef conservation efforts. Island number 3 belongs to HM the Thai Princess. Fishing is banned in Similan and Surin National parks. However, fishing boats are constantly seen in and around the park. When diving, one can often find nets stuck to reefs and illegal fishing traps. Park rangers are posted on several islands, but seem uninterested in anything beyond collecting national park fees, which must be paid in cash. As of February 2015, park entry fee is 500 THB, and divers need to pay an additional 200 THB per day. Thai nationals are eligible for a discount.
In recent years many illegal fishing traps have been found outside the most common dive sites. They have contained among others giant trevallies, batfish, barracuda, golden pilot jacks, and giant triggerfish. Fishing traps seem to be overly abundant around Ko Bon and Ko Tachai.
Access
Access to the Similan Islands is easiest from Khao Lak in Phang Nga Province. The mainland office is in Tab Lamu, which is a small fishing village, just 13 km from central Khao Lak, Phang Nga. Boats depart daily from the middle of October to the middle of May. The trip takes three hours each way on slow boats or 70 minutes via speedboat.
During the diving season liveaboard boats head to the Similan Islands. These dive boats depart and return from Khao Lak, Ko Lanta, Phuket, and Ranong and stay for several days at Similan National Marine Park.
According to the official website, the park is closed in the monsoon (from May 16th - October 14th) yearly. These dates are subject to change