Bottle and Glass Point is the rocky headland at the eastern end of Shark Beach in Nielsen Park, one of the harbour's grand Federation-era pleasure grounds, and it is the kind of dive that Sydney divers keep in reserve for the days when the ocean is unusable. From the eastern end of the beach the reef edge runs north for about 40 m and then bends north-east, an almost solid section of sandstone with small rocks along its foot, kelp on top and a little sponge life on the shaded faces, in 5–8 m of water. The route follows this edge until it turns sharply right, and a longer version continues east around the underwater point and back south-south-west to a rock exit at Coolong Road.

Fish life is the standard harbour cast – luderick, yellowtail, sweep, one-spot pullers, sea pike and flathead – with cuttlefish and octopus in the cracks and, when the Nielsen Park shark net is deployed between October and May, White's seahorses on its mesh; Vizzbud's Nielsen Park listing adds bream, leatherjackets and the occasional wobbegong under the rocks, and blue-ringed octopus are possible. Visibility is 3–6 m. Michael McFadyen's assessment is candid: 'worth a dive every couple of years' as a back-up, viable at night, not one of Sydney's premier sites.

Its practical problems are parking, which is extremely limited near the eastern end even in early evening during summer, and the crowds on the beach. Its merits are shelter from anything but a northerly, easy entry, and the pleasure of a swim in a national-park setting. It suits Open Water divers looking for somewhere new on a rough day, and night divers in winter when the park empties; the western end of the beach and the net are covered in the Nielsen Park / Shark Bay row.

Follow New South Head Road to Vaucluse and turn into Greycliffe Avenue; park near the corner with Coolong Road, as close to the eastern end of Nielsen Park as possible (extremely limited in summer, even early evening; paid NPWS car park inside the park). Gear up and walk across the park to the eastern end of the beach – about 150 m. Enter from the sand and head north along the reef.

Exit back at the beach, or continue east around the point and south-south-west to exit at Coolong Road and walk back to the car.

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. Nielsen Park faces north and is exposed only to a northerly wind; it is a summer swimming mecca and the park is crowded from October to April, when the shark net is in. In winter the net comes out and parking is easy.

Enter at the eastern end of the beach, descend and head north for about 40 m along the reef edge, follow it as it turns north-east through kelp and small rocks at 5–8 m until it turns sharply right, then return to the beach; or continue east around the underwater point and swim south-south-west to exit at Coolong Road.

No operator; independent divers as a rough-weather fallback.