Point Perpendicular is the towering northern headland of Jervis Bay, named by Captain Cook in 1770 and topped by the 1899 lighthouse. Below its cliffs is a series of dive sites, and the Sponge Gardens (also called Lighthouse Reef) is the classic multilevel dive among them. The bottom is sand at about 34 m, from which huge boulders covered in sponges and sea squirts rise towards the cliff, with smaller rock formations between them.

As divers ascend northward the boulders form gullies and swim-throughs, and in the 5–7 m zone huge rocks balanced on other rocks create excellent swim-throughs and a couple of very large caves. The colour is the draw: sponges, sea squirts, gorgonians in pink and red, and purple sponges cover the deeper rock, and Deep 6 describes delicate corals and colourful tunicates. Fish life changes with depth – black reef leatherjackets, wobbegongs, firefish and giant cuttlefish on the deeper boulders, grey nurse sharks occasionally below 30 m, and huge schools of yellowtail, seapike, ladder-finned pomfret, mullet, silver bream and sweep in the shallows. Port Jackson sharks arrive in early winter.

The flexibility of the profile – deep sponge gardens for Advanced divers, shallow caves for everyone – makes it one of the most regularly dived sites in Jervis Bay, and one of the listed marine park snorkelling spots in calm weather. The cliff-top lighthouse is visible from the boat but not open to the public; road access to the headland is through the Beecroft Weapons Range when it is open. From the water, divers should still check for live-firing closures.

Charters depart Huskisson (Dive Jervis Bay; boats in Currambene Creek). Private boats launch at Huskisson, Callala Bay or Murrays Beach (Booderee), or at Currarong's ocean ramp. From Huskisson cross the bay to the entrance and run along the outside of Point Perpendicular; Line up with the distinctive pyramid-shaped rock halfway along Point Perpendicular (about a third of the way from the headland's left edge) and head towards shore, dropping anchor when the depth rises to 25 m at 35° 05.551' S 150° 47.983' E.

About 20 minutes from Huskisson.

The outer Beecroft Peninsula cliffs face east to south-east and take the full force of any south-easterly or easterly swell; the sites are diveable in swell under about 1.5 m and are well sheltered from south-westerly and westerly winds, which make them the go-to sites in winter. North-easterly winds (common on summer afternoons) make the run from Huskisson across the bay entrance rough and cause surge on the northern-facing cliffs. Visibility is commonly 15–25 m and can reach 30 m in winter when clear oceanic water sits against the peninsula.

Currents along the cliffs are usually mild but can run at the bay entrance on a strong tide change. Defence live-firing closures can shut the sea area – check before going. Point Perpendicular faces south-east across the bay entrance and takes southerly swell directly; it is best in westerly and north-westerly weather.

Descend to the sand edge at 30–34 m and explore the sponge-covered boulders briefly, then ascend northward through the gullies and swim-throughs towards the cliff. Finish with the caves formed by balanced boulders at 5–7 m and the big fish schools in the shallows.

Dive Jervis Bay (Huskisson; boats Avalon and Genesis) runs double boat dives most days, and Deep 6 Diving Jervis Bay / other Huskisson operators also visit; site chosen on the day according to swell and wind.