Khao Lak diving day trips If you are staying in Khao Lak these are the dive trips available in high season. From May to October the Similan and Surin Islands marine parks are closed. Prices for December 2018 – April 2019 MONDAY Similan Islands 2 dives – 5,600 baht plus 700 baht NP fees Koh Bon & Koh