Back Beach Cray Reef is the offshore reef that lies about a kilometre out from Jubilee Point on the Sorrento ocean coast, in 6–20 m of Bass Strait water. The Scuba Doctor lists it primarily as a crayfishing site and describes incredible ledges and overhangs – the limestone of the peninsula, undercut by swell into long horizontal shelters that southern rock lobsters favour – and notes that it is equally good for exploring, fish-watching and photography. The reef top is kelp-covered and broken by gutters; the ledges beneath are lined with sponges, bryozoans, sea tulips and jewel anemones, and the fish are the standard back-beach community of sweep, old wives, magpie perch, boarfish, zebrafish and bluethroat wrasse, with Port Jackson sharks and draughtboard sharks resting under the overhangs, blue devils in the darker holes and weedy seadragons along the kelp margin.

Seals from the Heads colonies and passing dolphins are regular. It is one of a chain of similar cray reefs along the Peninsula's ocean side – Cape Schanck Cray Reef and Flinders Cray Reef are the others listed – and all share the same dependencies: a small boat, a flat sea and a gentle northerly. Access is via The Rip from Sorrento or Portsea, which adds the discipline of slack-water timing, or a longer run from Flinders.

There is no charter schedule and no mooring, so this is a site for divers with their own boat or a club with one. It suits Advanced divers comfortable on exposed coast, lobster hunters (in season, with a licence and measuring gauge) and photographers wanting ledges full of life in clean water without the tidal pressure of the Heads.

Launch at Sorrento or Portsea and cross The Rip at slack water, then run east along the back beaches to the marks off Jubilee Point – 20–30 minutes from Portsea; or launch at Flinders and run west along the coast, which avoids the Heads but is a longer, more exposed passage. Anchor on the reef in 8–12 m and descend the line. No charter schedules it; it is a private-boat and club site.

Best dived, in the source's words, with minimal swell and a gentle northerly rolling through; any south-westerly swell above about 1.5 m makes the anchorage and the shallow ledges uncomfortable and the Rip transit difficult. Current is slight but the boat must time the Heads at slack water. Visibility is usually good Bass Strait water and best in winter.

Descend the anchor to the reef top, work along the ledge line at 12–18 m checking overhangs for lobsters, then return over the shallower reef at 8–10 m to the anchor and ascend the line with a safety stop.

No regular operator – private boats and Peninsula dive clubs, occasionally Red Boats or Dive Victoria charters on request when the back beaches are flat.