Meet the site
Nepean Bay is the sheltered water on the inside of Point Nepean, between the tip of the peninsula and Observatory Point, and it is where Portsea charters go when the Heads are not an option. The Scuba Doctor listing describes 'scattered reef, lots of fish and scattered wreck debris' in 1–12 m, 'lovely shallow clear water sheltered from all winds except northerlies', and notes that it is 'suitable for end-of-day diving' – the easy second dive after a wall, or the training dive when the swell is up outside.
The reef is a series of low limestone patches and kelp beds on a sand floor, some of them covered by sand for months at a time and then exposed again, with the deeper ground toward the entrance side of the bay. Because the whole of Point Nepean and its waters are within the marine national park, the fish life is recovering and the listing notes that 'fish populations are gradually recovering': old wives, sweep, wrasse, leatherjackets, magpie perch and scalyfin are abundant and approachable, cuttlefish are common in winter, and rays and Port Jackson sharks lie in the gutters. Seals from the point pass through.
The wreck debris is a reminder of where the bay is. The rocks of Point Nepean and Corsair Rock have claimed ships for two centuries, and the wreckage of several of them – most notably the clipper Empress of the Sea, deliberately beached and burned here in 1861 – lies in and around the bay; the Empress and the two shallow sub-sites on the inside of the point, Inner West and Inner East – Radar, are listed separately, as is Sweep Reef on the ocean side. Scuba Doctor also lists the Isabella Watson (1852) on 'Nepean Reef'. For a diver, Nepean Bay is a place to relax: shallow, clear, sheltered, full of fish and dived on the ebb so that the tide, if it is felt at all, sets back toward Portsea.
What you might see
Old wife, silver sweep, bluethroat wrasse, leatherjackets, magpie perch, scalyfin, giant cuttlefish, smooth stingray, Port Jackson shark, southern rock lobster, kelp, sponges, Australian fur seal
Location
Sheltered bay on the north (Port Phillip) side of Point Nepean between the point and Observatory Point, 3 km west of Portsea; scattered reef and wreck debris; 215 m east-south-east of Nepean Bay Inner East – Radar.
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
scubadoctor.com.auscubadoctor.com.auparks.vic.gov.auRecord updated 27 Sept 2026. Source claims are being reviewed.
