Three Trees, Similan Islands - Thailand Dive Sites

Three Trees, named after the three trees directly above the dive site on Similan Island 9, is a big wide white sand channel with some awesome corals and fish encounters

Giant sponge coral, Three Trees, December 2022 © [email protected]

Two of these bommies are covered in soft corals and often glass fish. The bommies are big – a good 10 metres by 5 metres, so there’s plenty of room for a group of divers to circle around.

Barracuda in the deep, Three Trees, May 2024 © [email protected]

These are the warm up to the main attraction which is the giant barrel sponge at least two metres high which sits on a rock outcrop resplendent in the middle of the channel, surrounded by soft corals. It is an absolute whopper.

Soft corals, Three Trees, December 2022 © [email protected]

While the barrel sponge usually gets all the attention, there are some beautiful patches of soft corals hanging on to the rocks around the sponge which are worth a look too.

Orange fan, Three Trees, Similan Islands, December 2022 © [email protected]

There are also some lovely fan corals here too, which is all the more surprising given how fierce the current can get – they’re super resilient.

Soft corals on white sand, Three Trees, December 2022 © [email protected]

Further along and down deeper around 28 metres is another clump of rocks which seems to be a magnet for marine life – one time we were there a huge school of barracuda sailed in over the rocks, while on another occasion we were caught in the middle of a fusilier blizzard, with thousands of them rushing past us.

Running fusiliers, Three Trees, February 2024 © [email protected]

Be aware that to get from the entry point to the bommies and then onto the barrel sponge rock requires covering a fair bit of ground, so pace yourself. It’s hard for the boats to drop divers directly on the bommies because the current means you could easily miss them and then be drifting in the blue.

The chonky barrel sponge, Three Trees, February 2024 © [email protected]

Picking an entry time so it’s near slack tide is important as it can be ripping otherwise. A gentle drift between the bommies and then onto the side of the channel to explore the
shallows is ideal rather than getting swept off and surfacing out in the channel.

Yellow Snappers, Three Trees, May 2024 © [email protected]

All photos taken during Similan diving seasons 2022-2023 and 2023-2024. I’ll probably add more during the 2024-2025 season too. The Similan dive season runs from October to May each year. The Similan Marine National Park is closed from mid May to mid October each year, so don’t plan a liveaboard trip then!

Recommended Similan Liveaboards October 2025 to May 2026

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