Scuba Dive Milln Reef

great barrier reef school fish

Milln Reef sits along the outer bank of The Great Barrier Reef and is teaming with life and healthy corals.

Choosing our family’s location to experience the vast Great Barrier Reef for our first time was a daunting task. Luckily, the tour we chose anchored at Milln Reef. Milln Reef is home to the famous Three Sisters and Whale Bommie dive sites and is approximately 1.2 miles (2km) in length, with depths up to 100 feet (33m) off the sand. There are several wonderful dive spots here, providing excellent coral dive walls and swim-throughs. With a novice to intermediate rating, it is the perfect place for beginners and experienced to see what the Great Barrier Reef has to offer.

With a 3.5 hour sailing time from Cairns, most tour companies do not travel to Milln. A liveaboard tour was the best option for a more personalized and uncrowded experience.  Several companies provide liveaboard options. We toured with Coral Sea Dreaming for the two days and one night option. On a liveaboard excursion, you typically dive 4 times a day: once in the morning, twice during the day, and a night dive. This is by far the best “bang for your buck” for a bucket list experience.

great barrier reef coral puffer fish
Can you spot the puffer fish amount the colorful coral? [photo credit Ann-So Reimers]

There are more than 600 species of coral located within the Great Barrier Reef. The vibrant colors in these hard corals are hard to ignore contrasting in the bright blue water. The multi layering of these gorgeous calcium carbonate skeletons are the building blocks for the thriving reefs.

scuba great barrier reef milln
A scuba diver swimming past a large acropora hyacinthus coral reef. [photo credit Ann-So Reimers]

With mild currents and a visibility of 50-65 feet (15-20 meters), Milln reef provides a calm and beautiful atmosphere.  The white tipped reef sharks, sea turtles, barracudas, and an occasional bull ray will travel through this portion of the Great Barrier Reef.

buffer fish staghorn coral
A puffer fish seeking refuge in a large staghorn coral structure. [photo credit Ann-So Reimers]

There are shallow coral gardens bursting with life at the Milln Reef. Gorgonian fans filled with glassfish, colorful sponges, and sandy gardens home to the spotted eels. Schools of fusiliers and snappers and chub can be spotted as you glide about.

milln reef divers descending
Divers descending from Coral Sea Dreaming.

Whale Bommie is a perfect location for a night dive. There, you may see painted lobsters, sleeping turtles, and parrotfish, reef crabs, lionfish, squid, or whatever nature brings your way. With depths surpassing 65 feet (20 meters), you can expect a great adventure – The GBR is an underwater city that never sleeps!

Giant trevally great barrier reef scuba
Giant trevally at Milln Reef [photo credit Ann-So Reimers]
great barrier reef giant clam
Oh my gosh, this giant clam was…GIANT! [photo credit Ann-So Reimers]

The Giant Clam is the largest living bivalve mollusc. Being targeted for it’s meat, this is one of the most endangered clam species. At over 400 pounds and over 6 feet wide, these creatures can live to be over 100 years old. Swimming near this gorgeous animal brought an uneasy feeling, especially when it would constrict the mantle tissues as though it was going to clamp onto me. To respect his home, I enjoyed the beauty of this creation from a healthy distance.

coral sea dreaming diver
Diving at the great barrier reef is an amazing experience! [photo credit Ann-So Reimers]
great barrier reef turtle blue tangs
A green sea turtle peacefully swims by with a school of blue tangs. [photo credit Ann-So Reimers]

At Petja mooring on Milln Reef, it is almost guaranteed you are going to see the resident turtles. The sea turtles look like they are slowly flying through the water. But when they get spooked, they can move quickly. It is so relaxing watching these beauties in their habitat. We came across one turtle that seemed larger than our 6′ 8″ son!

great barrier reef scuba instructor
Our dive instructors were very good at making sure we stayed safe. [photo credit Ann-So Reimers]

Diving at Milln reef is a fantastic option if you are able. With the help of an experienced guide, or if you choose to go on your own with a buddy, you get an experience that will be hard to top with memories to last a lifetime.


  • Pick the optimal time of the year to visit the GBR. In November, the coral will spawn, giving a firework-like show of coral releasing their fertilized egg bundles into the water. Be sure to check for the arrival of the deadly box jellyfish that swarm the reef. They usually arrive between November-March. From June to October, the warm water is clear from lack of rain, and the migrating Humpback Whales bring their calves there to nurse.
  • Make sure you have a high-quality underwater digital camera or check to see if you can rent one from the company you cruise with. You don’t want to miss out on capturing this underwater wonderland.
  • Be responsible and help take care of the reef. Picking up after yourself and not touching the wildlife will help preserve this natural wonder for many years to come.