Drum Roll Please – Introducing a contender for Cairns’ best Great Barrier Reef dive site, the Three Sisters at Milln Reef. Dive right in to explore these three, large coral bommies which rise up 33m from the sea floor, to plateau just 1m beneath the surface. These ‘sisters’ are home to the most amazing, diverse and bountiful array of marine life. Dive around them to be surrounded by hundreds of fusiliers, snapper, trout, chromis, cod, barracuda and much, much more. Explore the swim throughs between them, which are festooned with large, vibrant gorgonian sea fans, beautiful cauliflower corals and feather stars. There are several sea turtles who call the sisters home and usually stingrays and sharks on the sandy sea floor. We loved it and you will too.
We love the Three Sisters dive site on Milln Reef. The fish, the sea fans, the turtles, the coral and the abundance of life is just amazing.
The Three Sisters dive site on Milln Reef is suitable for divers of all experience levels. From the sea floor to the top of its bommies, this site is teeming with life in all shapes, sizes and colours – it’s like a micro-example of all that makes the Great Barrier Reef ‘great’. Advanced divers can explore from its 30m depth upwards. Open Water divers will thrill at what awaits them 18m up and even Junior Open Water divers can enjoy the swim throughs, overhangs and crevices, 12m and upwards. This site has something for everyone. On the day we dived – Saturday 4 March 2023 – the highlight for us was definitely the swim throughs, sliding through the space between the bommies and being surrounded by sea fans, soft corals, feather stars and sea whips. That being said, the absolute abundance and diversity of life came in a very close second! Seeing sleeping sea turtles, schooling barracuda, sweetlips of all shades and sizes, coral trout and cod, anemonefish and much, much more. It’s an absolute delight exploring the Three Sisters site and this one is definitely on the list of Cairns’ best dive sites.
“We dived the Three Sisters at Milln Reef, on a day tour with Passions of Paradise. I think the words the Dive Master guide wrote on her slate, as we completed the safety stop, sum it up – ‘Best Dive Ever!’. It sure was and how exciting that this is where our son got to complete his 11th dive, as a certified Junior Open Water Diver on the Great Barrier Reef. We dived down, around and through the bommies for 45 minutes and it was just magic. It’s official – Three Sisters – we love you (and so did everyone else who dived this day).” – Julie Johnston
So let’s provide a little more information about Milln Reef and the Three Sisters dive site. Milln Reef is a part of the Great Barrier Reef World Heritage Area and Marine Park. It’s approximately 56km offshore from Cairns and is classified as an outer reef, being around 11km from the edge of the continental shelf. Milln Reef has several different dive sites, including ‘Club 10’, ‘The Drop’, ‘The Edge’, ‘The Whale’, ‘Swimming Pools’, ‘Petaj’, the ‘Three Sisters’ and more. It’s the ‘Three Sisters’ we’re writing about and only a few reef tour operators have permits to access the moorings here, Passions of Paradise is one of them and that’s who travelled with for this review.
The Three Sisters is known for its abundance and diversity of marine life, all of which can be seen when diving and exploring its coral walls, crevices, overhangs and swim throughs. We’ve mentioned the gorgonian sea fans, you don’t usually see them in such size and abundance when diving the reefs off Cairns. Here at the Three Sisters they are gold like honeycomb and as red as a fire-truck, they are big and they are beautiful and the cauliflower corals, sea whips and feather stars that grow and live alongside them, create a multi-layered sea garden, just waiting for you to explore. Beyond that, there are literally thousands of fish streaming in and around the Three Sisters, in all shapes, sizes and colours. We dived through and amongst hundreds of blue-lined fusiliers, stopped by barracuda, hovered to watch the small humbug fish dart in and out of their staghorn coral homes, glided over waving anemones with their clownfish residents and swam with snapper. It would be impossible for me to list every type of fish and marine creature we saw, but rest assured there were LOTS and that’s why we’re saying this is a contender for the best Great Barrier Reef dive site from Cairns.
“I actually completed my Open Water Diver certification on the Three Sisters site, many years ago. It was great to get back there, with Julie and Ethan as my dive buddies. I love taking underwater photos (and have taken all of the photos in this story) and the Three Sisters offers loads of photo opportunities. In addition, the Passions of Paradise boat had multiple camera ‘buckets’, so I felt my camera was safe between dives. The style of guided diving was awesome – it was not a race, just nice and slow. There were lots of fish and I definitely need to get back out there to get some photos of my favs – the diagonal-banded sweetlips – which were chilling around one of the sisters. The boat was spacious. The vis was good – I had a great time!” – Richard Johnston.
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So who goes to the Three Sisters at Milln Reef – there are only a few reef tour operators with mooring access at this beautiful dive site, Passions of Paradise is one of them and that’s who we went with. You can read our Passions of Paradise trip review on our I Love Cairns website. Passions of Paradise is one of the last locally owned and operated Cairns reef tours and has been operating since 1987. They have 24 private moorings across several different Great Barrier Reef reefs, including Milln and of course the Three Sisters. They provide day tours to and from Cairns and the Great Barrier Reef, visiting 2 different reef sites each day. The exact sites they choose to visit on any given day, are selected to provide guests with the best possible reef experience on the day, pending weather, wind and tides. So, there is no guarantee that if you book a Passions of Paradise reef day tour that you will actually visit the Three Sisters – but if the weather is right, then you might, because they love it too.
When travelling with Passions of Paradise you can do 2 scuba dives during the day, this is for certified divers and those wanting to try scuba diving for the first time on an introductory dive. Maximum dive time for certified divers is 50 minutes, pending air consumption. The Three Sisters dive site has a maximum depth of 33m and is suitable for divers of all certification and experience levels. All diving on Passions of Paradise is guided and the guide we had – Mathilde – was excellent, tailoring the dive to suit our interests and allowing time to look under crevices and overhangs. We had an excellent day with Passions of Paradise – great crew, great boat, great dive sites.
There is something magical about swimming through and with hundreds of fish, as they school around the coral gardens of the Three Sisters.
The Three Sisters dive site is located on Milln Reef, about 56km offshore from Cairns. Milln Reef is classified as an outer reef, being around 11km from the edge of the continental shelf.
There is no correct answer to this question, as all of the reef tour boats from Cairns are very professional. However, we travelled with Passions of Paradise, a locally owned and family operated boat. You can read our full review of the Passions of Paradise day tour on our I Love Cairns website.
LOTS!!! This dive site is renowned for the abundance and diversity of marine life. There are reef sharks and stingrays, sea turtles and sea fans, giant clams and starfish, feather stars and fusiliers, cods and chromis, trout and trevally, surgeonfish and snapper, anemonefish and angelfish – just so many fish! Of course being a ‘wild’ dive site there is no guarantee of the specifics of what you will see, but we can guarantee you will be more than impressed with the quality of this dive site.
The sisters – three large coral bommies – are on the eastern side of Milln Reef and are of varying heights. The deepest bommie is around 33m while the smallest one is 12m deep. This dive site is suitable for divers of all certification and experience levels.
Yes it sure is. The Three Sisters dive site is on Milln Reef, offshore from Cairns and part of the Great Barrier Reef World Heritage Area and Marine Park.
There is never a guarantee of what you may or may not see when scuba diving, however reef sharks are usually seen in the sandy areas surrounding the Three Sisters.
We have seen turtles every time we have dived at the Three Sisters. Again, we can’t guarantee what you will or will not see, but they are definitely there so it’s likely that you will.
The Three Sisters dive site is on Milln Reef, offshore from Cairns. Passions of Paradise is one of the reef tour operators to have a permit to use the Three Sisters mooring. Water entry is giant stride, with descent down the mooring line and the sisters, just a very short swim away. This dive site has all the feels for lovers of the Great Barrier Reef. Beautiful coral cover with a diversity of hard and soft corals, numerous fish species and evidence of a really healthy ecosystem. Passions of Paradise is a great boat and company, locally owned and operated from Cairns. They are committed to reef protection and education, with sustainability in operations and this is evident in all aspects of your day with them. This tour is suitable for divers of all experience and certification levels.
© Cairns Dive Guide 2026
