Low Isles snorkeling: what the lagoon is really like

Low Isles snorkeling happens in a sheltered lagoon rather than on a wall of open reef. Quicksilver, which has sailed here for decades, gives the snorkeling depth as 0 to 5 metres and notes that the corals sit close to the island.¹ Calypso, whose vessel runs the trip sold on this site, says you can reach the reef either off the back of its boat or straight from the beach, because the reef hugs the shore.² You float above sand, rubble and coral heads, with the white beach a few strokes behind you.

The reef is richer than its size suggests. Tourism Port Douglas Daintree counts 150 species of hard coral around Low Isles, although the reef is dominated by 15 species of soft coral.⁸ Parrotfish in blue, green and purple are a common sight, along with angelfish, damselfish, clownfish, trevally, sweetlip and moon wrasse.⁹ Quicksilver adds rabbitfish and surgeonfish to the grazers you meet over patches of algae.¹⁰ Slow down and the small life appears: sea cucumbers on the sand, butterflyfish moving between coral heads, a turtle lifting its head for air.

So, is Low Isles good for snorkeling? For a first reef day, yes, and for confident swimmers it is pleasant rather than spectacular. Quicksilver is frank about it: an inshore reef like this one gets more nutrients and fine silt, and murkier water, than the reefs offshore.¹¹ For water clarity, Tourism Australia points reef-goers from Port Douglas to the months of May to October.⁷ Some reviewers of the trip sold here found the water murky on their day, while others swam with turtles, so treat clarity as weather-dependent and the turtles as the likelier reward.

A guide turns snorkeling the Low Isles reef into a lesson. Quicksilver's Wavedancer runs a snorkeling demonstration on the way out, and its listing adds a marine biologist talk before arrival and a guided beach walk once you are there.¹² Sailaway's full-day listing names a guided snorkel tour led by a marine naturalist, plus a glass bottom boat trip and a heritage walk. On a guided swim you stay in a loose group, the guide dives down to show you a clam or a hidden fish, and you surface with questions.

The animals most people hope for are the turtles. Calypso says giant green sea turtles are frequently sighted at Low Isles and reef sharks are quite common, while being honest that nothing can be guaranteed.²⁷ Look also for giant clams: Tourism Port Douglas Daintree describes them as living around 100 years in the wild and sometimes weighing more than 200kg.²⁸ The Reef Authority asks snorkelers to keep over a metre clear of giant clams, so admire the colored mantle from above.²⁹

Small details make the swim easier. If you wear glasses, ask before you board: Sailaway keeps prescription snorkeling masks on its boats.²⁴ Spit or defog the mask, push your hair out of the seal, and keep the snorkel on the side away from the guide's hand signals. Breathe slowly through the mouth and let the fins do the work with long, lazy kicks from the hip. When you want to stop, roll onto your back and float rather than standing up, because the bottom is reef, not a swimming pool floor.

Low Isles has a longer scientific record than almost any reef, and it helps to know it before you swim. A British and Australian team lived on the island in 1928 and 1929, and its leader, Maurice Yonge, wrote that every pool held fish that needed an ichthyologist, a poet and an artist to describe.^49,50,26 Their work became the baseline later scientists measure against, which is why researchers keep coming back.

The comparison is not all good news. When Yonge returned in 1978 he found the reef surface he had known almost entirely dead, and he blamed sediment carried by the Daintree River after rainforest clearing.⁵¹ A 2018 survey for the Global Coral Reef Alliance found the shallow reef flat, once covered in hard corals, now dominated by soft corals and algae.⁵² Earlier work in the 1990s had measured phosphate and phytoplankton at four to five times their 1920s levels.⁵³

That history explains what you see today. Expect soft corals, coral heads in patches, seagrass, fish and turtles rather than an unbroken garden of branching coral. It is a living, changing inshore reef, and snorkeling it with that in mind makes it more interesting, not less. If bright hard coral in clear blue water is your only goal, read our comparison of Low Isles and the outer reef before you book.