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
Click any score to see a detailed breakdown
Marine Life
82.0Species diversity, megafauna encounters, reef fish abundance, macro life, and endemic 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.
“Thailand's best diving by a mile. Liveaboard through the park, hit Richelieu Rock on the way.”
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.
- →Open water between islands can be choppy. Liveaboards handle it, speedboats not so much.
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.
When to dive it
Every dive shop gives you this briefing at 7am. We just wrote it down. Tidal dependency: slight. Optimal window: Nov-May only — park closes for monsoon. Liveaboard is the way..
- Vizhigh
- Currentmild
- Crowdlight
- Elephant Head Rock
- Christmas Point
- wide angle
Thailand's premier dive destination. Morning on Elephant Head Rock — massive granite boulders with swim-throughs and fan corals.
- Vizhigh
- Currentmild
- Crowdmoderate
- East of Eden
- coral gardens
- macro on rubble
East side calmer in afternoon. West side gets afternoon swells. Trust the schedule.
Dive forecast
Realistic conditions by month. Viz ranges are what you should actually expect, not best-case marketing numbers. Confidence % is the share of days that match this profile historically.
| Month | Viz (m) | Temp (°C) | Current | Sea | Rain | Confidence | Highlights |
|---|---|---|---|---|---|---|---|
| Jan | 21–35 | 32 | Mod | Calm | Dry | 88% | conditions vary |
| Feb | 20–32 | 33 | Mod | Calm | Dry | 88% | conditions vary |
| Mar | 20–32 | 33 | Mod | Calm | Dry | 88% | conditions vary |
| Apr | 21–35 | 34 | Mod | Calm | Dry | 88% | conditions vary |
| May | 22–38 | 34 | Mod | Calm | Dry | 78% | conditions vary |
| Jun | 22–38 | 33 | Mod | Chop | Light | 65% | conditions vary |
| Jul | 21–35 | 32 | Mod | Chop | Light | 55% | conditions vary |
| Aug | 20–32 | 32 | Mod | Chop | Wet | 55% | conditions vary |
| Sep | 20–32 | 32 | Mod | Chop | Wet | 65% | conditions vary |
| Oct | 21–35 | 33 | Mod | Chop | Wet | 78% | conditions vary |
| Nov | 22–38 | 33 | Mod | Calm | Light | 88% | conditions vary |
| Dec | 22–40 | 33 | Mod | Calm | Dry | 88% | conditions vary |
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.
Liveaboard rhythm
intermediateFour dives a day for four days. Pacing and nitrogen management.
Granite boulder navigation
foundationalSwim-throughs and overhangs require fin clearance awareness.
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.
- Koh Tao61.2Thailand
Same country, complementary diving style.
- Richelieu Rock61.6Thailand
Same country, complementary diving style.
- Hin Daeng & Hin Muang64.3Thailand
Same country, complementary diving style.
- Khao Lak76.2Thailand
Same country, different dive character. Easy to combine in one trip without extra flights.
- Phuket74.9Thailand
Same country, different dive character. Easy to combine in one trip without extra flights.
- Koh Lipe69.7Thailand
Same country, different dive character. Easy to combine in one trip without extra flights.
Liveaboard options
Marco Polo Liveaboard, Thailand
The MV Marco Polo offers dive trips to the Andaman Sea from November-April. The M/V Marco Polo has 6 cabins onboard, accommodating 12 guests. Visit the Similan Islands, Surin & Richelieu Rock.
Budget Liveaboards in Thailand
Dive Thailand on a budget. Find affordable liveaboards, perfect for backpackers and divers looking for a great value dive trips!
Thailand Liveaboards for October, 2027
Discover the best Thailand liveaboard trips for October, all with our Best Price Guarantee. Secure your 2027 dive adventure today, and simply pay later
Diving Similan Islands
Richelieu Rock scuba diving
Raga Liveaboard, Thailand
The Raga is a 37-meter (121-foot) liveaboard for 28 guests exploring the stunning Similan Islands, Koh Bon, Richelieu Rock, and more with up to 14 dives in the Andaman Sea.
Camic, Thailand
Join the MV Camic liveaboard for a 4 or 5-night itinerary to the Similan Islands. Dive Richelieu Rock, Koh Bon, and Koh Tachai for the chance to see manta rays, leopard sharks, and turtles.
Thailand Liveaboards for December, 2026
Discover the best Thailand liveaboard trips for December, all with our Best Price Guarantee. Secure your 2026 dive adventure today, and simply pay later
Thailand Liveaboards for November, 2026
Discover the best Thailand liveaboard trips for November, all with our Best Price Guarantee. Secure your 2026 dive adventure today, and simply pay later
Sawasdee Fasai, Thailand
The recently renovated Sawasdee Fasai liveaboard offers dive and snorkel cruises in the Andaman Sea. Explore the Similan Islands and Richelieu Rock in comfort with AC cabins, huge sun deck and outdoor lounge area.
Manta Queen 6, Thailand
Explore Thailand’s top dive sites aboard Manta Queen 6 with 15 dives over 4 days, including Similan Islands, Koh Bon, and Richelieu Rock.
Deep Andaman Queen, Thailand
The MV Deep Andaman Queen offers luxury diving in the Andaman Sea, Thailand. Explore the Similan Islands or the Mergui Archipelago in comfort .
Best dive types here