North Harbour Aquatic Reserve

Quick Facts on Diving North Harbour Aquatic Reserve

• Location: This reef is located from the inner point of North Head west into the north of Sydney Harbour.
• Diver Qualifications: Open Water and above
• Depth: 10m to 36m
• Recommended Gas: 21% or Nitrox
• Dive time: Generally, 35-70 mins
• Visibility: Over 10m to 30m
• What you’ll see: Soft corals and sponges, weedy seadragons, yellowtail, frogfish, anglerfish, Port Jackson sharks, crested horn sharks, wobbegong, bronze whaler sharks, nudibranch, crimson-banded wrasse, bull rays, whiting, starfish, moray eel, large crayfish.
• Best season to dive: Great in all seasons

Many scuba dive sites

We offer many dive sites in this area of North Head.

• Old Mans Hat
• Adamson Sponge Gardens
• Red Indian Reef
• Waterfall, and
• Fairfax Lookout

We dive several spots along this area and mix up the anchoring depths depending on several factors such as diver certifications, tide height or the incoming or outgoing tide.

The sand line is the best as it gets us under the surface water which is generally dirtier. For coral density, Adamson Sponge Gardens is the best. This dive site is located 15m at the southern end of Old Mans Hat.

Old Mans Hat gets its name from a flat rock that balances atop of the sheer cliff. To old timers the rock looked like a top hat. It’s a spectacular Sydney dive site. It features over 60 species of colourful soft corals and sponges and a large (45-degree angle) boulder field dropping down to a sand line at 18m to 23m.

Frogfish or anglerfish can be seen hiding in wait for their next meal among the coral that are shaped like bowls or vases. The striped anglerfish is the most common, but white-fingered anglerfish and (the black one) the white-spotted anglerfish are also seen on this dive. Anglerfish are very common around the harbour wharves, particularly at night.

There are sharks too on this Sydney dive

Our North Head Marine Sanctuary dive features several species of shark; most notably Port Jackson sharks, crested horn sharks and of course, wobbegong (commonly referred to as carpet sharks.) Very occasionally, we’ll even see bull sharks and bronze whaler sharks cruising at the surface.

Colourful residents and stunning undersea decors

Amazing soft corals

Old Mans Hat includes good-sized caves and swim throughs filled with stunning Alcyonacea or soft corals (formerly known as gorgonian sea fan corals.) These amazing living creatures can grow up to 1.5m in size and come in orange or yellow. They’re much less common nowadays as divers used to collect them for the aquarium trade. The largest one we’ll encounter is 1m in size – and it’s stunning!

Old Mans Hat – a great second dive

Kelp gardens start at around 16m in depth and extend up to the 10m deep area where huge boulders are found.

Navigating though this area is like driving around small houses and can be great fun when the visibility is good, generally on the high tide.

An octopus’ garden with sponges!

With the thermocline comes the visibility changes as the dirtier surface water makes way for the clearer, saltier water below. Visibility varies greatly depending on tides and depths, but expect 10m to 15m most days, and if you’re very lucky, you could even hope for 25m or more once a month.

Red Indian Fish can be found in this area. They’re rare in Sydney due to the aquarium trade and are easily recognisable by their colourful main which looks a lot like an American Indian ceremonial feather head dress.
Dwarf Lionfish also abound. You’ll mainly see them at night in vase or bowl-shaped coral.

Spiny or red gurnards can also be seen in numbers around February. These fish have Freddy Kruger-type “flingers” on the mid-sections of their brightly coloured pectoral fins. The gurnards will walk around the sand lines of Old Mans Hat or off a number of wrecks located in and around the harbour entrance such as the Paddle Steamer PS Herald.

The Catherine Adamson Wreck

A protected wreck

Classified as a ship, the largest of the old wood-hulled types, the Adamson had a complement of 3 masts (foremast, mainmast, mizzen mast), each fitted with a topmast, top-gallant mast and royal mast (each square-rigged.) This wreck site is protected under the Shipwrecks Act. Taking any artefacts is strictly forbidden.

Off the sand line extending out are flat rock plateaus with soft corals and hard corals which support marine life like the weedy seadragons. On this part of the dive, you’ll also find the spiral eggs of the crested horn shark. The shark’s egg has a twisted tendril at its end which the shark attaches to the base of corals or kelp. (Port Jackson shark eggs are very similar. They are fist-sized without tendrils. The sharks will jam the eggs into rocks cracks to let them gestate to term.)

Fairfax Lookout Dive

The Fairfax Lookout dive is located at the inner point of the North Harbour Aquatic Reserve at the entrance to Sydney Harbour. It’s a short 10-minute boat ride from our other dive locations and a great location for a dive as the high headland provides protection from the wind.

At Fairfax Lookout, you’ll find a boulder field on a 45-degree angle which drops down to 18m. At this depth you’ll see gorgeous colourful sea sponges and soft coral gardens. Divers will then make their way towards the reef, edge down a small boulder field to between 23m to 28m where they’ll encounter big black bull rays with up to 3m wing spans, huge schools of whiting and many small caves and swim throughs to explore.

Shipwreck debris

On this Sydney dive, you’ll discover shipwreck material from several old ships lost in the late 1800s.

A commonly encountered fish on this dive is the crimson-banded wrasse. The female is plain in colour and you’ll find these fish quite inquisitive as they are very much attracted to bright lights.

As this area is a marine sanctuary where commercial or recreational traps are forbidden, you’ll be able to see large crayfish (some over 4kg) during the dive. They will often be seen out walking around divers with little fear. Also on display: moray eels, colourful sea stars (starfish) and nudibranch.

Come dive with us!

Discover the North Harbour Aquatic Reserve with Sydney’s with Sydney’s best dive crew.