The Similan Islands and Surin Islands national parks officially close on 15 May (and re open on 15 October 2015) but the liveaboards will stop running at the end of April. So you still have a few weeks to jump on a boat and do the best snorkeling in Thailand.
- Sawan (Reggae Queen) has 3 day 3 night trips to the Similan and Surin Islands plus Koh Bon and Koh Tachai departing every Wednesday and Sunday evening from Khao Lak. The last scheduled trip is 26-29 April. www.snorkelingthailand.com/3-day-3-night-andaman-sea/
- Malee has 2 day 1 night trips to the Similan Islands departing from Khao Lak on Mondays and Wednesdays. She also runs 3 day 2 night trips to Similan, Koh Bon and Koh Tachai departing Friday mornings and returning Sunday evening. The last trip is scheduled for 27-28 April. www.snorkelingthailand.com/sanuk-snorkeling-liveaboard/
- Oktavia has a 2 day 2 night trip to the Similan Island 10-12 April and a 3 day 2 night trip to Koh Bon, Koh Tachai and Richelieu Rock on 13-15 April. There is also a 5 day 5 night trip 16-21 April. www.snorkelingthailand.com/oktavia-snorkeling-liveaboard/
If you are here from May to October you will not be able to visit the Similan Islands. We recommend a short liveaboard to the Phi Phi Islands or the Racha Islands. Giamani has overnight trips to Phi Phi and 2 day 3 night trips that include Phi Phi and Racha Noi. www.snorkelingthailand.com/phi-phi-snorkeling-liveaboard/