Boulder City (Similan)
Also known as: Shark Fin Reef
Best time to dive
November to April; December to March
What you might see
- BarracudaLikely
- Manta rayPossible
- Moray eelLikely
- Napoleon wrassePeak season
- NudibranchLikely
- Sea turtleLikely
- Whale sharkLikely
Sightings are seasonal probabilities, not promises - even in peak season nature does its own thing.
Certification & difficulty
Advanced Open Water - advanced conditions (currents/depth); dive within your training.
Snorkelling
Not a snorkel site - Limited - boulder tops snorkelable in calm conditions but primarily a scuba site
Safety notes
Strong/unpredictable currents, deep sandy bottom (35-40m) requiring dive-time and decompression management, boat traffic near moorings
Permits & fees
Mu Ko Similan NP entrance fee: 500 THB/day foreign adult, 250 THB foreign child (3-14); 100/50 THB Thai adult/child; usually collected by the boat operator or at the park checkpoint. Park open ~15 Oct/Nov-15 May, closed ~16 May-14 Oct each year (exact reopening date varies by year)
Permits and operators change - confirm before booking.
Location
Nearest hub: Khao Lak
This profile is desk research, compiled from public sources - not a first-hand dive report. Coordinates are approximate.