The Cod Hole is a spectacular swim-through at the end of the island. It is quite big, so a small group of divers fits in it comfortably. The entry is at around 15 meters and it takes you down to approximately 18 meters depth. In and around the Cod Hole there are usually large schools of huge fish such as Jewfish and Kingfish, very common are schools of Sweetlips and Trevally as well. Inside the Cod Hole, you can generally find lots of big fish again including some big cods, a few Wobbegong Sharks and lots of smaller marine life such as Mooray Eels, Cuttlefish, Crayfish, Cleaner Shrimps, Slipper Crabs and Lionfish. Going past the Cod Hole, the sandy bottom starts at 20 meters and gradually gets deeper. This area is one of the best spots at Julian Rocks for large Pelagics. You never know what you might see out there. The sand trenches behind the Cod Hole are also very popular with Grey Nurse Sharks during the colder months from June to November. During summer there is a good chance of seeing a Manta Ray near the Cod Hole. All year round, the area around the Cod Hole tends to attract many big rays such as Eagle Rays and Bullrays. It is also a good spot to see giant Queensland Gropers.