Southeast Asia · Thailand
Surin Islands
Thailand's best shallow hard-coral gardens, in five to twelve metres
Photo: The Cosmonaut · CC BY-SA 2.5
Mu Ko Surin is a national park of five granite islands near the Myanmar border, and its shallow hard-coral gardens are the best in Thailand — broad plates of Acropora in 5 to 12 m, largely spared the anchor and trampling damage that hit the country's southern reefs. The Moken sea nomads still live seasonally in the bay at Ao Bon. Diving is easy and shallow, and the park closes entirely for the south-west monsoon.
About diving in Surin Islands
Three kinds of trip land here. Liveaboards out of the Khao Lak coast fold Surin into their Similan and pinnacle itineraries, working the islands through the settled part of the day and moving on overnight. The second is a speedboat run from the mainland pier, which makes the crossing most of the day's effort and leaves room for a couple of dives before the return. The third never gets on scuba at all: park tents and bungalows on the beach, and snorkelling straight off the sand.
The diving is horizontal rather than vertical. There are no walls; the islands are ringed by granite shelves that slope away gently, and you spend the dive swimming over the top of the coral rather than alongside it. What current there is collects in the channels between the islands, so those get run as drifts and timed to the tide while the rest of the park stays close to slack. Bottom times run long because the interest sits shallow, well inside no-decompression limits.
Warm-water years have hurt these reefs, and the park has closed individual sites before to let bleached coral recover, so guides swap the plan without much notice. What holds up is the format: bright, shallow, wide-angle reef that reads about as well through a snorkeller's mask as it does on scuba. That makes it a good fit for mixed groups where not everyone is certified, and for anyone happier spending an hour above living coral than staring into blue water.
Best time to dive Surin Islands
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Season | Prime | Prime | Prime | Prime | Off-season | Off-season | Off-season | Off-season | Off-season | Off-season | Good | Prime |
| Sea surface | 28°C82°F | 29°C84°F | 30°C86°F | 30°C86°F | 30°C86°F | 29°C84°F | 29°C84°F | 29°C84°F | 29°C84°F | 29°C84°F | 29°C84°F | 29°C84°F |
| Daytime high | 29°C84°F | 30°C86°F | 31°C88°F | 32°C90°F | 31°C88°F | 30°C86°F | 29°C84°F | 29°C84°F | 29°C84°F | 29°C84°F | 30°C86°F | 29°C84°F |
| Rain | 80 mm3.1 in | 45 mm1.8 in | 91 mm3.6 in | 156 mm6.1 in | 372 mm14.6 in | 425 mm16.7 in | 471 mm18.5 in | 459 mm18.1 in | 523 mm20.6 in | 377 mm14.8 in | 267 mm10.5 in | 152 mm6.0 in |
| Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|
| Prime | Prime | Prime | Prime | Off-season | Off-season |
| Sea surface | |||||
| 28°C82°F | 29°C84°F | 30°C86°F | 30°C86°F | 30°C86°F | 29°C84°F |
| Daytime high | |||||
| 29°C84°F | 30°C86°F | 31°C88°F | 32°C90°F | 31°C88°F | 30°C86°F |
| Rain | |||||
| 80 mm3.1 in | 45 mm1.8 in | 91 mm3.6 in | 156 mm6.1 in | 372 mm14.6 in | 425 mm16.7 in |
| Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|
| Off-season | Off-season | Off-season | Off-season | Good | Prime |
| Sea surface | |||||
| 29°C84°F | 29°C84°F | 29°C84°F | 29°C84°F | 29°C84°F | 29°C84°F |
| Daytime high | |||||
| 29°C84°F | 29°C84°F | 29°C84°F | 29°C84°F | 30°C86°F | 29°C84°F |
| Rain | |||||
| 471 mm18.5 in | 459 mm18.1 in | 523 mm20.6 in | 377 mm14.8 in | 267 mm10.5 in | 152 mm6.0 in |
2011–2025 averages. Sea surface: NOAA Coral Reef Watch, measured at the surface, so deeper water can run colder. Daytime high and rain: NASA POWER.
The national park closes mid-May to mid-October for the south-west monsoon; Feb–Apr is the peak of the open season.
Best months: January, February, March, April, December
Surin Islands water temperature and weather by month
The sea surface stays between 28 and 30 °C (82–86 °F) all year. Most rain falls from May to October, peaking at about 520 mm (20 in) in September; it stays largely dry from December to April. Daytime highs sit around 30 °C (86 °F) all year. The coldest water here is about 27 °C (81 °F), so pack a 3 mm, or even a 2 mm, suit.
Dive types & marine life
Turtles are the dependable sighting right through the November-to-April open season. Add reef fish in quantity over the shallow coral, blacktip reef sharks in the shallows, cuttlefish and octopus, and nudibranchs along the rubble margins. Large pelagics are rare here; that diving belongs to the pinnacles further offshore.
- Reef
- Coral garden
- Drift
- Muck & macro
- Night
- Sea turtles
- Reef fish swarms
- Nudibranchs
- Macro critters
- Reef sharks
- Pristine corals
- Octopus & cuttlefish
- Barracuda
Best dive sites in Surin Islands
Shallow coral-block reef the dive tables list as a night dive
Reef
Scattered boulders on sand, with overhangs holding the fish life
Pinnacle
A current-swept pinnacle from 30 m to within 5 m of the surface
Reef
Calm ten-metre sand and coral bay used for training and night dives
Blacktip reef sharks over a granite slope on the western side
Reef
Coral plateau that breaks the surface, and a ridge out at 30 m
A 40 m drop-off on the west side, with 20 to 30 m of visibility
Reef
Shallow hard-coral shelf that works for snorkellers and divers alike
Chong Kad
Channel between the two main islands, drifted over coral and sand.
HQ Channel
Sheltered site by the park headquarters, used for check dives.
How to get to Surin Islands
Day boats leave Khuraburi pier in Phang Nga, roughly two to three hours north of Phuket airport by road, though many divers arrive instead on a Khao Lak liveaboard working the offshore circuit. Everything is boat access. The park shuts from mid-May to mid-October, taking the island tents and bungalows with it.
Photos from Surin Islands
The Cosmonaut · CC BY-SA 2.5
The Cosmonaut · CC BY-SA 2.5
The Cosmonaut · CC BY-SA 2.5
The Cosmonaut · CC BY-SA 2.5
Dive videos
Scuba diving in Surin islands with The Smiling Seahorse · The Smiling Seahorse on YouTube
Scubadiving Thailand - Surin Islands · WE-WorldExplorers on YouTube
Photo credits
- Turquoise Chong Khad Bay curves around a forested hillside on Surin Island, Thailand by The Cosmonaut, CC BY-SA 2.5, via Wikimedia Commons
- A weathered granite boulder sits in clear turquoise shallows in Chong Khad Bay, Surin Islands by The Cosmonaut, CC BY-SA 2.5, via Wikimedia Commons
- Empty white-sand beach fringed by rainforest on North Surin Island, Thailand by The Cosmonaut, CC BY-SA 2.5, via Wikimedia Commons
- A large granite boulder rests on an exposed reef flat at low tide, North Surin Island by The Cosmonaut, CC BY-SA 2.5, via Wikimedia Commons
- Panoramic view of a low-tide reef flat and sandy shore between two of the Surin Islands by The Cosmonaut, CC BY-SA 2.5, via Wikimedia Commons
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