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Ao Suthep, Surin Islands, Thailand

Ao Suthep is beautiful hard coral garden in the Surin Islands, often visited by Similan island diving liveaboards and accessible by snorkellers visiting the Surin Islands too.

Hard coral levels, Ao Suthep
Hard coral levels, Ao Suthep © chris@divehappy.com

Despite having been diving in the Similan Islands since 2004 and visited the Surin islands several times, I never dived Ao Suthep until December 2022. Geographically it’s one of the Surin Islands’ many bays with a pristine beach. Underwater, though, is where the real magic is.

Juvenile barracuda over the reef, Ao Suthep, Surin Islands
Juvenile barracuda over the reef, Ao Suthep, Surin Islands © chris@divehappy.com

Having dived it twice now – the first time under gloomy grey skies in December 2022, the second in February 2023 under early morning sunshine, it’s quickly become one of my favourite sites on a Similan Islands liveaboard trip.

Table corals and staghorn, Ao Suthep, Surin Islands
Table corals and staghorn, Ao Suthep, Surin Islands © chris@divehappy.com

The reason is because Ao Suthep has some do the most abundant and intact hard corals I’ve seen anywhere in Thailand. Tables corals are piled up on one another, with stag horn and plate corals covering every inch of space.

Dory fish and other reef fish around Ao Suthep's corals
Dory fish and other reef fish around Ao Suthep’s corals © chris@divehappy.com

Small reef fish shuttle around over, under and into the corals, using its countless hideyholes for shelter, food and safety. The reef feels truly alive. The density of the corals and the way they’re stacked up on each other, decades of growth still intact, makes itfeel like you’re drifting over an alien cityscape.

Sunburst over hard corals, Ao Suthep, Surin Islands
Sunburst over hard corals, Ao Suthep, Surin Islands © chris@divehappy.com

The real joy is that this isn’t one small part of the reef – it stretches on unbroken for several hundred metres.

Hard coral garden from above, Ao Suthep, Surin Islands
Hard coral garden from above, Ao Suthep, Surin Islands © chris@divehappy.com

The size of the corals can be staggering, some over three metres wide, endlessly growing outwards and upwards and their delicate structures still surviving the rigours of the ocean’s occasional violent force and the ever present threat of human intervention.

Layers of staghorn corals and table corals
Layers of staghorn corals and table corals © chris@divehappy.com

The reason the reef is so rich in this particular bay – apart from it being escaped dynamite fishing and being destroyed by boat anchors – is because many of the nutrients caught up in the ocean currents down from the Mergui Archipelago in Myanmar get swept into Ao Suthep bay and remain here, providing the food for the coral to survive and thrive.

Five layers of table corals, Ao Suthep, Surin Islands
Five layers of table corals, Ao Suthep, Surin Islands © chris@divehappy.com

The nutrients can make the water cloudy and the visibility less clear than the often gin clear waters of the Similan Islands, but it’s a small price to pay to see such a healthy reef.

Dense corals, Ao Suthep, Surin Islands
Dense corals, Ao Suthep, Surin Islands © chris@divehappy.com

How To Get To The Surin Islands

As well as Similan Islands liveaboards visiting the Surin Islands (check availability and pricing on Liveaboard.com), there are also snorkelling daytrips to the Surin Islands.

Both the snorkelling trips depart from Thap Lamu pier which is about 15 minutes drive from Khao Lak. Thap Lamu pier is about an hour’s drive from Phuket Airport.

You can check flights to Phuket, buses to Phuket and buses to Khao Lak on 12go.


Similan Liveaboards Overview

Upcoming Similan Liveaboard Availability and Pricing

Check availability and pricing for all Similan Islands liveaboards departing in

(The Similan National Park is closed from mid May to mid October each year)

Similan Liveaboards Trip Reports

Photos from each of the Similan liveaboard trips I've been on over the years.



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Considering travel insurance for your trip? World Nomads offers coverage for more than 150 adventure activities including scuba diving, as well as emergency medical, lost luggage, trip cancellation and more.

Start Planning Your Thailand Dive Trip Now!

:: Check the availability and pricing of liveaboards in Thailand and book online.


:: Find the cheapest flights to Thailand - Phuket (airport code: HKT) is the nearest airport for diving the Similan Islands. You can get direct international flights to Phuket or go via one of Bangkok's two airports - Suvarnabhumi (BKK), the main airport, or Don Mueang (DMK), the low cost carrier terminal.


:: Make sure you don't forget to bring any of the essentials for your scuba diving trip with our comprehensive Liveaboard Packing List


:: World Nomads offers simple and flexible travel insurance. Buy at home or while traveling and claim online from anywhere in the world.


:: Find available places to stay in Phuket for before and after your liveaboard on Booking.com - usually you can reserve a room with no upfront payment. Pay when you check out. Free cancellations too.


:: Need inspiration? See our Best Places To Dive In Thailand for ideas of where to go and what to do.


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