Burrill Rocks is the signature dive of Ulladulla and one of the best temperate reef dives on the NSW coast. A group of rock outcrops rises from a sand floor about a kilometre offshore, south of Ulladulla Harbour and opposite the entrance to Burrill Lake. The northern wall tops out at 9–10 m, while the southern side drops beyond 23 m to sand. What sets it apart is the terrain: the rocks have split and collapsed into a jumble of boulders, leaving canyons and caves between them. Most caves are only a metre or two wide, but several are large, and many link up so you can move from one to the next with an exit never far away.

The best-known feature is the Arch, a larger cave entrance that is usually full of hundreds of silver sweep hanging in the gloom. North of the usual anchoring area the main cave system runs through the boulder field; to the south, another cave and tunnel open onto a sheer wall that is the dive's other highlight. Overhangs throughout are packed with fish: yellowtail, one-spot pullers, red morwong, eastern rock blackfish, luderick and the endemic eastern blue devilfish, which sits in most dark recesses. Old man snapper (Tasmanian trumpeter) are occasionally seen. Walls and cave ceilings carry sponges, sea squirts and small gorgonians.

Michael McFadyen rates it alongside Fish Rock Cave and the Poor Knights as one of the best temperate dives he has done, and the local shop lists it as its headline site. Visibility is often good by South Coast standards. The dive suits competent Open Water divers who have good buoyancy and are comfortable in overhead environments with daylight exits. Those who prefer to stay in open water can have an equally good dive following the walls. It can be dived several times without repeating a route, and a current running west gives the option of an easy drift along the rocks.

Boat access only. Charters and private boats launch from the public ramp inside Ulladulla Harbour, reached off the Princes Highway in the centre of Ulladulla (about three hours' drive south of Sydney); there is trailer parking around the harbour and the dive shop is a short walk away. From the harbour mouth the boat turns south past Warden Head and runs about 4 km down the coast to the rocks off Burrill Lake, 10–15 minutes in reasonable seas.

McFadyen recommends anchoring on the reef in about 20 m; the old public mooring was removed around 2014, so boats now anchor on rock clear of the cave entrances and divers descend the line.

The rocks sit about 1 km off an open coastline and take swell from the south, south-east and east; a southerly swell above about 1.5 m creates heavy surge in the shallow caves and makes anchoring on the northern side awkward. Best on a westerly or light north-westerly after several days of small swell. Strong north-easterly afternoon sea breezes in summer make the ride back choppy but the dive itself is usually still possible in the morning.

Current is common and can be used for a drift west off the rocks. Visibility drops after heavy rain when Burrill Lake is open to the sea.

Anchor in about 20 m and decide on north or south. Heading north takes you into the main cave system: follow the boulder field and enter the Arch, the largest cave, then work through the interconnected caves and canyons, using the many exits. Heading south, a cave and tunnel lead out to the prominent South Wall in 20–23 m.

Return along the wall top at 10–12 m and do the safety stop on the rocks rather than mid-water. With current, run a drift west and have the boat follow.

Swim-throughs are short with daylight exits; do not push into the smaller passages without cavern training.

Dive Adventures Ulladulla visits regularly on its RIB MV Duckunder (lists the site at max 30 m, standard 15–22 m) whenever the sea allows; visiting Sydney clubs and private boats from Ulladulla Harbour also dive it. No other charter operates out of Ulladulla.