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.

Pook with the giant barrel sponge, Three Trees, Similan Islands, December 2024 © [email protected]

You may only get a chance to be here for a minute or so as currents can pick up quickly and the barrel sponge is right in the middle of the channel. It is well worth the drive-by viewing.

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 from the giant barrel sponge, at around 28 metres, is another clump of rocks which seems to be a magnet for marine life.

Boots and the giant barrel sponge, Three Trees , Similan Islands, November 2024 © [email protected]

It’s not always possible to go further and deeper into the channel to check out the rocks, but it’s definitely worth a look.

Barracuda Tornado 20, Three Trees, Similan Islands, Thailand, December 2024 © [email protected]

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. But you don’t always need to be deep to find the fish – in December 2024, we saw a spectacular barracuda tornado at Three Trees right at around 12 metres. See the separate Barracuda Tornado page for more photos and details.

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]

Three Trees’ giant barrel sponge is a Similan Islands landmark and it’s heartening to see that it continues to thrive.

Pook and the giant barrel sponge, Three Trees, Similan Islands, February 2023 © [email protected]

All photos taken during Similan diving seasons 2022-2023, 2023-2024 and 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 Similans liveaboard trip then!