The name Koh Haa Yai literally means '5 islands and the big one', with Koh Yai being the 'big island' (we normally call it Koh Haa Yai) at the west of the archipelago, and the other 5 islands making up the remainder of this diving and snorkeling paradise.
Each of the 6 Koh Haa islands are quite different, with most being too big to fully cover in a single dive.
This means that we actually have 12+ dive sites around these wonderful islands and we recommend that divers try to make at least two Koh Haa dive trips during their stay on Koh Lanta.
Diving Koh Haa Yai
As the largest of the Koh Haa islands, Koh Haa Yai is home to several very different dive sites and probably the largest amount of coral and marine life in this amazing archipelago.
The extensive coral coverage around this island provides several dive sites, dramatic underwater scenery, and extensive coral gardens, slopes and bommies.
We often see larger fish such as barracudas, golden and blue-fin trevally hunting schools of snapper and fusiliers along the reef. Malabar groupers are common, waiting patiently in the shadows, ready to ambush their unsuspecting prey.
Pufferfish, trumpetfish, wrasse, moray eels, soldierfish, groupers, cornetfish, surgeonfish, triggerfish, schools of snapper, nudibranchs, lionfish, and countless other species can be found around this island.
There are a great many interesting and seldom seen smaller and macro species found around Koh Haa Yai if you take a little time to look. Perfect for the underwater photographer.
Koh Haa Cathedral
There are three caves on the south west side of Koh Haa Yai, and approaching from the west, the first cave is smallish and only for the more comfortable/experienced diver.
The second cave is quite a bit larger, more like a cavern, and is connected to the third cave via a large 'window'.
It is this third, cavernous cave which is famously known as 'The Cathedral' and is a 'must' for any suitably experienced diver when visiting the Koh Haa islands.
For those without any ear equalising problems, it's also possible to surface in The Cathedral where there is fresh air and some limited daylight shining through from the entrance. This is best done near the start of the first dive, before nitrogen has a chance to accumulate in your body.
There are two main snorkeling areas around Koh Haa Yai, a rocky and coral encrusted plateau near The Cathedral, and the stony beach facing The Lagoon.
Both snorkeling spots are home to many hard and soft corals, schools of tropical fish, and other marine life such as starfish, sea cucumbers, urchins, sponges, octopus, squid, cuttlefish, sea snakes, and occasional hawksbill turtles.
It's not uncommon for snorkelers to see schools of parrotfish or sea chubs swarming the reef shallows, munching on algae, or find themselves surrounded by damselfishes, fusiliers, or even a school of barracuda slightly further out in the blue.
Diving Koh Daeng
Koh Daeng (Red Island) is the smallest island to the north of Koh Haa Yai, and is attached to Koh Yai by a short coral/sandy ridge. Some people call this Koh Haa Six, but the traditional Sea Gypsy name is Koh Daeng.
What looks like a small island on the surface actually spreads out underwater into an extensive reef area with walls, slopes and coral gardens surrounding the island.
In the shallows of Koh Daeng we can really see the red colour of the rock on this island. The shallows are also the perfect place to see schools of moorish idols feeding on the algae which covers these rocks in the shallows.
The reef around Koh Daeng mostly drops to 25 - 30 m, however the connecting ridge to Koh Haa Yai is more in the 12 - 15m range, with gentle slopes on either side.
On the outer (north) side of Koh Daeng, the smallest of the Koh Haa Islands, we may occasionally see a whale shark cruising past in the blue.
Diving from Koh Daeng to the rocky Beach area on the east side of Koh Haa Yai is a very nice dive, and makes an excellent drift dive in a dropping tide.
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Koh Haa Tides & Currents
When planning dives around the Koh Haa islands, is it worth remembering that a dropping tide will generally run north to south, and a rising tide will generally run south to north.
Some of the Koh Haa dive sites make excellent drift dives when currents are stronger around a full moon or a new moon.