Khao Lak Explorer

Khao Lak Explorer is the modern face of Similan diving — a large, superbly reviewed dive center running the full Khao Lak menu, with liveaboards of two to five nights through the Similan and Surin islands, long-range day trips to Richelieu Rock, local wreck and reef days, and PADI courses at every level. The operation's scale shows in the good ways — well-kept boats, organized logistics, multilingual staff — while the review scores show it hasn't traded personal attention for size; the shop's ratings are among the best of any dive operator in Thailand.

The menu makes it the flexible choice. Divers short on days can hit Richelieu on a day trip, while the liveaboards remain the proper way to do the Similans, waking up at the sites before the day boats arrive.