The Portsea Hole Wreck is a small deliberate addition to Victoria's most-dived deep site: a 13 m wooden fishing boat sunk in the early 1980s as an artificial reef and dive attraction about 70 m past the eastern end of the Portsea Hole wall, in 25–27 m on the flat at the edge of the South Channel. The Scuba Doctor listing records that the authorities initially objected to the scuttling on the grounds that it was a navigation hazard – a concern, as the listing dryly notes, that its 26 m depth makes questionable.

Four decades on the hull is a reef in its own right. The listing describes it as 'now covered with sponges and other biological growth that has attracted numerous fish species', and the growth is the same filter-feeding community as the wall a few metres away – encrusting and finger sponges, ascidians, hydroids, zoanthids – with the fish concentrated around the structure: bullseyes and old wives in the hull, blue devils in the shadows, leatherjackets, wrasse and goatfish, and nudibranchs and seahorses in the growth. The timber is soft and the wreck is small enough to see in a few minutes, but it makes a natural turn point for a Portsea Hole dive and a target for navigation practice.

The practical issue is depth: the whole dive is at 25–27 m with no shallower option until the wall is regained, which is why the listing rates it Advanced and prescribes the flood slack so that the returning ebb sets divers back toward the hole. It is a common extension on Advanced deep dives and on nitrox dives, and it is worth doing once for the contrast between an overgrown timber hull and the natural wall beside it.

As for Portsea Hole: five minutes by charter from Portsea Pier (Dive Victoria Group, Bayplay), 15 minutes from Queenscliff (Red Boats), or by private boat from Sorrento Boat Ramp 4 km to the east. The wreck lies 70 m beyond the eastern end of the Portsea Hole wall on the flat at 25–27 m, and most divers reach it by swimming east along the base of the wall rather than from a separate drop; a boat wanting to shot it directly uses the GPS above, which is verified from the 'Shipwrecks Around Port Phillip Heads' book. Shipping check and dive flag as for the hole.

It is dived only on slack water at the end of the flood (SWF), so that any current after the turn carries divers back into the bay rather than out through The Rip. Slack water at Port Phillip Heads does not coincide with high or low water: it falls roughly three hours after high or low water at Point Lonsdale, and the usable window is typically 20–40 minutes. Use the Ports Victoria / Port of Melbourne slack-water predictions for The Heads (also republished by charter operators and WillyWeather 'Rip Bank') rather than a standard tide table.

Inside the Heads it is sheltered from most swell, but a south-west swell over about 2 m still surges across the top of the wall and a westerly or south-westerly wind over 15–20 knots makes the boat work unpleasant; big seas outside drop visibility to a few metres for a day or two. Visibility is best in late summer and autumn (Feb–May) when the water is clear and the westerlies have eased; winter brings 11–13 °C water and bigger swells but often the clearest days after a run of settled weather. Heavy rain has little effect this close to the ocean.

The listing's advice is specific: 'You should dive at flood slack, so when the tide turns, the ebb flow will assist your return to Portsea Hole.'

Descend the Portsea Hole shot at flood slack, drop to the sand at 27 m and swim east along the base of the wall and out across the flat for about 70 m to the wreck. Circle the hull once, then return west – the young ebb will help – to the wall and ascend it to 12 m for the DSMB ascent; nitrox and a conservative computer plan are advisable given the whole dive is at 25–27 m.

Dived from the same boats and often on the same dive as Portsea Hole: Dive Victoria Group and Bayplay (Portsea) daily/weekly, Red Boats (Queenscliff) frequent.