Anchor Reef is one of a chain of little-known boat dives along the Kurnell cliffs between the Botany Bay entrance and Cape Solander, sites that for decades were overlooked because Sydney divers headed for the famous shore dives inside the bay or the Eastern Suburbs. It lies about 600 m south of The Leap, and the layout is typical of this coast: a reef wall on sand, with the bottom coming up from 22–23 m to an 18–19 m reef top. The wall itself is modest in height but broken by small overhangs and cracks, with one or two isolated rocks standing off it on the sand at about 18 m.

The most interesting section is a gully running westward through large boulders, where a big rock sitting on top of the reef and a boulder beside it form a good swim-through. Across 25–30 m of sand to the west is a second wall built from large rocks, with small gullies and several excellent swim-throughs. The sand edges are worth searching: McFadyen reports weedy sea dragons and serpent eels there, while eastern blue devilfish and large cuttlefish hide under the overhangs.

Over the reef are schools of one-spot pullers, yellowtail and seapike, and he once met a grey nurse shark here – a reminder that the species moves along this coast between the known aggregation sites. Visibility can reach 20 m, but because the site is at the mouth of Botany Bay it suffers when dirty water flows out on the ebb, so a high or incoming tide gives the best results. There is no regular charter, so this is a private-boat or club dive, 15 minutes from the Botany Bay ramps.

It suits Advanced divers who enjoy exploring and navigating a site that has not been fully mapped, and it makes a good alternative when The Leap or Inscription Point are crowded with shore divers.

Boat only – the Kurnell cliffs are sheer and in Kamay Botany Bay National Park, with no practical shore entry. From Botany Bay, launch at Kyeemagh (Cooks River), Foreshore Road or Bonna Point (Silver Beach, Kurnell), run out past Captain Cook's Landing Place, Inscription Point and The Leap, then turn south along the cliffs; from Port Hacking (Gunnamatta Bay/Tonkin Park or Lilli Pilli ramps) run out past Bass and Flinders Point and north-east along Bate Bay past Cronulla Beach and Cape Baily. From the Botany Bay ramps it is about 15 minutes: pass The Leap and continue south roughly 600 m.

McFadyen's GPS is 34° 00.5500' S 151° 13.9283' E. Run in until the sounder comes up from 22–23 m to 18–19 m and anchor on the reef top near the wall. No dive boat operates here regularly.

The Kurnell cliffs face east to south-east, so they catch north-east, east and south-east swell; plan on seas under about 1.5 m. Being close to the Botany Bay entrance, visibility drops on the ebb when dirty bay water flows out, especially after rain – dive on a high or incoming tide. The site sits just outside the bay entrance, so it has some shelter from southerly swell behind Cape Solander but is open to north-east and east seas.

Visibility around 20 m is possible on a good incoming tide but can be poor after rain or on a big ebb. Afternoon north-east sea breezes in summer make anchoring and recovery uncomfortable.

From the anchor head to the wall and follow it north, looking at the flattened reef area, then return along the wall and continue south to the westward gully with its boulder swim-through. Cross the 25–30 m of sand to the west to the secondary wall of big rocks with gullies and swim-throughs, then return east to the anchor. It takes several dives, even with a scooter, to see it all.

No regular charter – private boat or dive-club (St George Scuba Club) only