Nielsen Park is the harbour's great Edwardian bathing park, a sweep of lawn, fig trees and heritage changing sheds above Shark Beach on Shark Bay, Vaucluse, run by the National Parks and Wildlife Service, and on a summer Sunday it holds thousands of swimmers. Divers use it mainly in the quieter months. The bottom is clean sand under the netted enclosure, dotted with rocky outcrops and kelp toward both ends, and the western rocks run out toward Steel Point with more structure and depth (8 m); the eastern end is Bottle and Glass Point, covered separately.

Vizzbud rates the entry 'very easy, suitable for all levels' and notes bream, leatherjackets, seahorses and the occasional wobbegong under the rocks. The interest is small-scale: White's seahorses on the net when it is in (roughly October to May), pipefish and juvenile fish in the kelp, octopus, cuttlefish and blue-ringed octopus under the rocks, stingarees and flathead on the sand, luderick, bream and yellowtail in the water column, and in autumn the tropical juveniles that colour every harbour beach. Visibility is 3–6 m, poor after rain.

It is a beginner's dive and a snorkel rather than a destination, but it has virtues: a sheltered north-facing beach that is flat in any southerly, good facilities, a cafe, and the pleasure of diving in a national park ten minutes from Double Bay. Parking is the difficulty – the car park fills early and the park is crowded in summer – so April to September, or an early morning, is the time. Nielsen Park suits new divers, families with snorkellers, and photographers with a macro lens on a calm evening; it should be read with the Bottle and Glass Point row as two ends of the same beach.

From New South Head Road, Vaucluse, turn into Greycliffe Avenue and enter Nielsen Park (NPWS pay-and-display car park off Greycliffe Avenue; arrives early on summer weekends or it is full). Walk 100–150 m down through the park to the beach. Enter from the sand at the western end near the changing sheds and follow the rocks west toward Steel Point, or the net line out.

Exit back onto the beach, where there are showers and toilets.

Inside South Head the ocean swell is broken; the eastern harbour shore dives are exposed only to wind chop and, in the case of Camp Cove and Green Point, to a north-westerly or northerly blow that puts a short sea onto the beaches. They are at their best in a southerly, which flattens them completely, and on the top of a flood tide when clean ocean water has come in through the Heads (visibility 5–10 m; 15 m on a rare winter day). After heavy rain the harbour is brown for days and the dives are not worth doing.

Boat and ferry traffic is intense on summer weekends and public holidays, when the bays fill with anchored craft; early mornings, weekdays and nights are the times to dive. Shark Beach faces north and is chopped by a northerly or north-westerly wind; in a southerly it is flat. The shark net is in from about October to May; in winter it is removed and the beach is quiet.

Low visibility after rain from harbour run-off.

Enter at the western end of the beach and follow the rocky outcrops and kelp west along the shore toward Steel Point at 4–8 m, checking under rocks for wobbegongs and octopus, then return along the outside of the net line searching the mesh (in season) for seahorses, and finish over the sand inside the enclosure.

No regular operator; independent divers and snorkellers, occasional Dive 2000 course or night dives when Camp Cove is crowded.