The reef beneath the Cape Solander whale-watching platform is, in McFadyen's words, one of the most interesting spots he has dived in Sydney – high praise from someone with thousands of local dives. It was discovered by John Beddie, a member of his dive club, and takes its name from the platform built on the headland to shelter the volunteers who count humpback whales during their northern migration, mostly in June and July. The layout is complex.

The main feature is a sheer wall on the western, shoreward side, dropping from 12–13 m, with a distinctive L-shaped corner. East of the anchorage the reef ends at a second, deeper wall where the bottom falls from 19 m to 22–23 m. Between the two is a rocky bottom with caves and overhangs: the first cave, home to an eastern blue devilfish, is within 20 m south of the usual anchorage and a larger one further south is big enough to swim through.

To the north are large boulders and a crack 0.5–0.75 m wide and about 5 m deep. The walls carry sponges, sea squirts and nudibranchs, and the fish and invertebrate life is excellent – one-spot pullers, silver sweep and yellowtail in schools, many species of leatherjackets and plenty of cuttlefish. On the sand and reef edges McFadyen lists Port Jackson sharks, weedy sea dragons, stingrays, numbrays and eagle rays.

A second mark just to the south, the Whale Watching Rockfall, is equally good and the two are worth several visits each, ideally with a scooter or nitrox. Visibility is usually 12–20 m, although an outgoing tide carrying dirty bay water can reduce it. It suits Advanced divers who like caves, walls and exploring, and it is one of the best reasons to take a private boat out of Botany Bay.

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 head out of the bay and south along the coast about 1.5 km past The Leap to the Cape Solander headland, identified by the whale-watching platform structure on top of the cliff – about 15–20 minutes.

McFadyen's GPS is 34° 01.0534' S 151° 13.9959' E; anchor where the depth comes up from 22 m to 18 m. Cape Solander Drive through the national park leads to the lookout but there is no shore access for divers.

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. Cape Solander is more exposed than the sites just inside the entrance: south-east swell wraps around the headland and big easterly seas create surge in the caves at 12–18 m.

Outgoing tides can bring dirty bay water if Botany Bay is particularly murky, but McFadyen has had 15 m visibility at low tide after heavy rain. Calm winter westerly days are ideal, and humpback whales pass close in June–July.

Descend onto rocky bottom at 18–19 m and head south: the first cave (with a resident blue devilfish) is within 20 m, then a larger cave you can swim through. Turn east across the reef to the deeper wall and follow it south about 40 m, then back north past the boat and west to the sheer main wall with its L-shaped corner. Finish in the boulder area rising to 15 and 12 m.

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