Julian Rocks – Cod Hole

Julian Rocks - Cod Hole

By ScubaDownUnder Team · 2026-04-27

# [Julian Rocks](https://www.scubadownunder.com/dive-sites/julian-rocks) - [Cod Hole](https://www.scubadownunder.com/dive-sites/cod-hole)

The Cod Hole is one of the named dive sites within the [Julian Rocks Marine Sanctuary](https://www.scubadownunder.com/dive-sites/julian-rocks-marine-sanctuary), two and a half kilometres offshore from Byron Bay. The rocks themselves are now officially called Nguthungulli, the Bundjalung name meaning "Father of the World", a recognition formalised in 2023 of the site's longstanding cultural significance. Underwater, the Cod Hole is a swim-through reaching twenty-one metres, with resident large reef fish, schooling pelagics, and the chance of grey nurse sharks or leopard sharks depending on the season.

## Quick stats

| Detail | Info | |---|---| | Region | Byron Bay, NSW | | Skill Level | Intermediate | | Depth Range | 10-22 m | | Typical Visibility | 10-15 m | | Water Temperature | 20-26 degrees C | | Best Season | October to April | | Access | Boat from Byron Bay, around twenty minutes |

## The site and its history

Nguthungulli has been a sacred site for the Bundjalung people for thousands of years. When sea levels were lower, around seven thousand years ago, people walked out to the rocks to conduct ceremonies. The site retains its cultural significance today, and divers visiting the sanctuary are guests in a place of importance to the Traditional Owners.

The rocks were declared a marine reserve in 1982 after sustained pressure from local divers and conservationists, with all fishing and commercial exploitation banned within five hundred metres. The Cape Byron Marine Park followed in 2002, and a sanctuary zone within the park was declared in 2006. The cumulative effect of more than four decades of protection is visible in the resident fish populations, particularly in the larger species that cannot recover quickly from fishing pressure.

## The dive

The Cod Hole sits on the eastern side of the Julian Rocks complex, where a swim-through cuts between rocks and opens onto deeper water. The dive typically starts in twelve to fifteen metres on the entry side, works through the gap, and finishes around the eastern wall in twenty metres or so. The structure here is reef and boulder rather than coral, which suits the temperate-tropical mix of fish life on this part of the coast.

The cod of the name are large blue gropers and their smaller relatives, holding position in the deeper holes. They are unbothered by divers and often allow close approaches, which makes the Cod Hole one of the more reliable encounter sites in the sanctuary. Big morays, wobbegongs, and the occasional resident shark also use the swim-through structure for shelter.

## Marine life

Julian Rocks sits at the meeting point of warm East Australian Current waters and cooler temperate currents from the south, which produces an unusual species mix for the latitude. Beyond the resident gropers and morays, common sightings include snapper, large eagle rays, wobbegongs in the shallows, and turtles year-round.

The sanctuary is internationally known for two seasonal aggregations. From May to October, grey nurse sharks gather here, sometimes in numbers approaching twenty individuals at a single site. The grey nurse is critically endangered along the east coast of Australia, with population estimates dropping below three hundred animals at one point in the early 2000s after decades of misguided shark-control fishing. Julian Rocks is one of about a dozen recognised critical habitats for the species.

In summer, from December to April, leopard sharks aggregate at the rocks in numbers that put Julian Rocks among the world's largest gatherings of the species. On a good summer dive a diver can drift over a sandy patch and count dozens of resting leopard sharks within visibility range.

## Conditions and safety

Currents around Julian Rocks vary with tide and swell, and the Cod Hole is sometimes on the working side of the current, meaning a brisk swim back to the boat. The intermediate rating accounts for the current exposure and the depth, so divers should be confident with neutral buoyancy and free ascents.

Visibility holds up well by NSW standards, ten to fifteen metres on a normal day, and can stretch to twenty when the warm current is well in. Boat traffic in the area is heavy during peak season, so a surface marker buoy on ascent is sensible practice.

The grey nurse sharks at Julian Rocks are docile and do not pose a threat to divers, but their critical-habitat status means there are clear etiquette rules about not blocking their swim paths or driving them out of the gutters where they shelter. Operators brief divers on these expectations before the dive.

## Getting there and facilities

The site is accessed by boat from Byron Bay, with several operators running daily trips. The boat ride is short, around twenty minutes, and most operators run two dives at different sites within the sanctuary. There are no facilities at the rocks themselves, but Byron Bay has full dive shop and rental support for visiting divers.

Tide and weather are the main determinants of which Julian Rocks sites are dived on a given day. The Cod Hole works in most conditions but is at its best on slack water with a slight outgoing current.

## Gear and photography notes

The depth and current at the Cod Hole sit comfortably within standard recreational gear, but the boat traffic in the area makes a surface marker buoy essential on every ascent. A delayed-deploy SMB shot from the safety stop is the standard practice. A torch is useful for working under the swim-through ledges, where the resident species shelter, and for picking out [the colours](https://www.scubadownunder.com/dive-sites/the-colours) of the reef invertebrates in the deeper sections.

Photography at Julian Rocks rewards lens choice by season. In summer, with the leopard shark aggregation in residence, wide-angle is the obvious answer for sandy-bottom sequences with multiple animals in frame. In winter, with grey nurse sharks holding in the gutters, both wide and mid-range work, depending on whether the goal is the school or the individual portrait. Macro shooters have a steady supply of nudibranchs, small wrasse, and the resident invertebrate life along the swim-through walls.

The grey nurse sharks are docile but their critical-habitat status means etiquette matters. Operators brief divers on this before the dive: do not block their swim paths, do not drive them out of the gutters where they shelter, and do not chase. The same applies to the leopard sharks: they tolerate respectful approaches but will move off if pushed.

## Combining with nearby sites

The Cod Hole is one of several named sites within the Julian Rocks complex, and most operators rotate between them across a two-tank day. The Nursery, Hugos Trench, the Marine Sanctuary boundary, and the open swim-throughs on the northern side all sit within the same boat trip and offer different perspectives on the same protected ecosystem. A weekend in Byron Bay can comfortably take in four or five distinct dives at Julian Rocks without repeating sites.

For divers travelling further along the coast, Julian Rocks pairs naturally with the South Solitary Islands further north and the Tweed Heads sites including [Cook Island](https://www.scubadownunder.com/dive-sites/cook-island) to the south. Both clusters share the East Australian Current and the temperate-tropical species mix, but each has its own character. A north-coast dive trip that takes in Julian Rocks plus one of these neighbouring complexes covers the strongest temperate-tropical diving in NSW.

## Final notes

The Cod Hole offers a tighter, more focused dive than the open swim-through sites elsewhere in Julian Rocks. For divers stepping up from open-water-rated sites, it is a sensible introduction to current and structure. For experienced divers, it is a productive site that rewards repeat visits across the seasons, with the species mix shifting from leopard sharks in summer to grey nurse aggregations in winter and resident reef life year-round.