Similan Islands Diving — Thailand
The Similan Islands open only from October to May and reward the timing with some of the best visibility in Southeast Asia. Massive granite boulder formations create swim-throughs and overhangs draped in soft corals, while the deeper sites bring manta rays and the occasional whale shark.
- Score
- 64.2 / 100
- Country
- Thailand
- Region
- Asia-Pacific
- Area
- Phang Nga
- Nearest airport
- Phuket (HKT)
- Visibility
- 15–40 m
- Water temperature
- 30–35 °C
- Max depth
- 40 m
- Current strength
- moderate
- Dive types
- cave, pelagic
- Best months
- November, December, January, February, March, April
- Minimum certification
- Open Water
- Access type
- boat
- Average 2-tank dive cost
- $120 USD
- Budget tier
- mid range
- Key species
- manta ray, whale shark, seahorse, nudibranch, frogfish, whale
- Google rating
- 0 (0 reviews)
- Top operators
- Sea Dragon Dive Center, Khao Lak Explorer, Wicked Diving
- Nearest hyperbaric chamber
- SSS Hyperbaric Chamber, Phuket (~60 km)
SCORE
8.6500°N
97.6500°E
The Similan Islands open only from October to May and reward the timing with some of the best visibility in Southeast Asia. Massive granite boulder formations create swim-throughs and overhangs draped in soft corals, while the deeper sites bring manta rays and the occasional whale shark.
Thailand's Crown Jewel Marine Park
Score Breakdown
Marine Life
82.0Species diversity, megafauna encounters, reef fish abundance, macro life, and endemic species.
Click any score to see a detailed breakdown
Key Species
Dive Types
Traveling with Non-Divers?
Your non-diving travel companions will find plenty to enjoy topside while you're underwater. Here are some activities to consider.
Activities for Non-Divers
Non-Diver Partner Score
Dedicated dive destination — not ideal for non-divers.
Safety & Emergency
Dive Insurance
Dive insurance is essential. Standard travel insurance often excludes scuba diving. We recommend DAN (Divers Alert Network) for comprehensive dive accident coverage.
Learn More at DAN.orgLiveaboard or day boat access; speedboat to Khao Lak/Phuket (1-2 hrs) for medical care
Top Operators
Sea Dragon Dive Center
PADI
Khao Lak Explorer
PADI
Wicked Diving
SSI
What your dive shop won't tell you
The minimum certification printed on a brochure is the legal floor, not the honest recommendation. Here's what we actually think you should bring to this site.
Below this we'd send you somewhere easier first.
What will challenge you
- →Moderate currents. Expect to drift — this is not a skill-builder site for a first trip after certification.
- →Recreational limit of 40 m is reachable here (max depth 40 m). Gas planning and NDL tracking matter.
- →Overhead environment. Standard recreational training does not cover you past the entrance. People die here doing what they'd do on an open reef.
What will surprise you
- →Thermoclines can drop water temp by 5°C between the surface and depth. Your wetsuit choice should match the minimum, not the average.
Photography brief
Subjects are only half the shot. A perfect macro site is useless in a three-knot drift, and a wide-angle dream is useless at 35 m with a murky ceiling. These are the conditions, not the hype.
Recommended kit
- →Macro lens (60mm or 105mm), focus light, dual strobes positioned for fill
- →Two independent light sources minimum; video lights beat strobes in caverns
What this site will teach you
The dives that made you a better diver are the ones that made you uncomfortable for the right reasons. Here's what this site will quietly train you for.
Overhead environment awareness
advancedCavern-zone diving teaches line awareness, light discipline, silt management, and the habit of always knowing where the exit is. These are the fundamentals of every overhead dive you'll ever do.
Deep profile discipline
advancedMax depth 40 m puts you at the edge of recreational limits. You'll build NDL tracking instincts, gas reserve management, and safety-stop discipline you can't get on 18 m reef dives.
7-day trip, per person
Rough ranges anchored to existing regional data — not booking quotes. Land-based trip, standard breakdown.
Hostels, shore diving, cheap eats
- Flights (RT from US)
- $1,100–$1,300
- Accommodation / day
- $50–$100
- Diving / day
- $100–$120
- Food / day
- $10–$25
- Transfers + misc
- $50–$150
3-star hotels, standard boat ops, mix of restaurants
- Flights (RT from US)
- $1,550–$1,850
- Accommodation / day
- $120–$220
- Diving / day
- $120–$160
- Food / day
- $30–$60
- Transfers + misc
- $50–$150
Top resorts or liveaboards, premium operators
- Flights (RT from US)
- $2,250–$2,750
- Accommodation / day
- $260–$500
- Diving / day
- $160–$200
- Food / day
- $70–$140
- Transfers + misc
- $50–$150
Flights priced round-trip from a major US hub. Figures are per person on a shared room. Solo travelers add ~30% to accommodation.
Build a trip around it
Most divers fly across the world for one destination and don't realise another worth-it site is 90 minutes away. Here are the honest pairings.
- Raja Ampat81.4Indonesia
Regional neighbour with a different dive type. Worth the extra flight if you want variety.
- Sipadan Island81.3Malaysia
Regional neighbour with a different dive type. Worth the extra flight if you want variety.
- Komodo National Park78.4Indonesia
Regional neighbour with a different dive type. Worth the extra flight if you want variety.
- Tubbataha Reef76.0Philippines
Regional neighbour with a different dive type. Worth the extra flight if you want variety.
- Okinawa68.5Japan
Regional neighbour with a different dive type. Worth the extra flight if you want variety.
- Tioman Island66.9Malaysia
Regional neighbour with a different dive type. Worth the extra flight if you want variety.
Best dive types here