Osborn Shoal West covers the western wall of the shoal, midway between the main Osborn Shoal mark and the South West corner, and links the two into a single easy dive. The reef top sits at 11–12 m, with sharp drops to 18 m or more on the eastern, northern and southern sides of the shoal, but here on the western side the wall first falls to about 15 m and then deepens gradually to 17 m. The wall varies from 2 to 3 m high and is riddled with small overhangs and cracks, while numerous boulders have tumbled off it onto the sand.

McFadyen describes large gorgonians and colourful sea tulips (sea squirts) on the walls, and the western side has the larger overhangs of the shoal. The fish life is the main attraction: huge numbers of ladder-finned pomfret, yellowtail and old wives shelter in the crevices, with luderick and seapike around the reef. Port Jackson sharks rest under the ledges in winter and blue gropers cruise the top.

The standard plan follows the wall south to the South West corner and back, a comfortable 40–50 minute dive at 15 m. As far as McFadyen knows, only the St George Scuba Club dives this spot, so the reef is in good condition and rarely disturbed. The site is 5–10 minutes from Port Hacking, making it a convenient choice for a second dive or when deeper sites are unworkable.

It suits Open Water divers, trainees and photographers who want a relaxed dive with plenty of fish.

Boat only. Launch in Port Hacking at Tonkin Park/Gunnamatta Bay (Cronulla), Lilli Pilli or Grays Point and run out past Bass and Flinders Point and Oak Park into Bate Bay. Osborn Shoal lies directly off Cronulla Beach, 5–10 minutes from the Port Hacking entrance; head north-east past Oak Park towards Cape Baily Lighthouse.

The traditional marks are the middle of The Kingsway at Cronulla (west) and the Potter Point outfall breather pipes against the dune ridge immediately left of Cape Baily Lighthouse (north). Anchoring on the reef itself holds poorly – drop on the sand edge and let the boat swing onto the reef. McFadyen's GPS is 34° 03.5086' S 151° 11.1700' E.

In westerly or north-westerly winds run to the north-west and drop anchor once over the wall; in other winds anchor on the east side of the shoal with plenty of rope so the boat drops back over the wall.

Bate Bay faces south-east and is open to swell from the east through to the south; southerly and south-easterly seas over about 1.5 m make the Bate Bay reefs rough and the Port Hacking bar can be dangerous in big swell. North-westerly and westerly winds give the calmest conditions; summer north-east sea breezes chop up the bay in the afternoon. After heavy rain, Port Hacking and the Cronulla stormwater drains discolour the inshore water.

Visibility typically runs 9–12 m, often over 15 m and occasionally 20–25 m on clean incoming water. In north-easterlies approach from the south-west; in southerlies work into the wind; in westerlies approach from the sand side.

Swim west from the anchor to the wall and follow it south for 12–15 minutes to the South West corner, which makes a good turning point, then return north past the anchor along the larger overhangs of the western wall and finish on the reef top looking in the cracks.

No regular charter – private boat or dive-club (St George Scuba Club) only; no charter boat currently operates out of Port Hacking.