Ingoldsby Reef is the broad, shallow limestone reef system that lies offshore between Point Addis and Anglesea, inside Point Addis Marine National Park, and it is the park's principal boat dive. It is named in Parks Victoria's material as the site of the 1902 wreck of the iron barque Inverlochy, which struck the reef in fog on a voyage from Glasgow to Melbourne and whose scattered plates and fittings still lie among the rock. Peter Fuller's dive log describes it as a lush shallow reef system with a great diversity of algae, dived to a maximum of 10 m in 8 m visibility for 50 minutes, and remarks on a crayfish walking about unconcerned in the open, something only seen in a marine reserve.

That is the character of the site: a wide platform of eroded calcarenite, mostly 5-10 m deep, canopied with crayweed, bull kelp and a striking variety of red and brown algae, cut by gutters and ledges whose undersides carry sponges, ascidians and bryozoans, and populated by the Surf Coast fish community in unfished numbers: blue-throat wrasse, magpie perch, leatherjackets, scalyfin, zebrafish, old wives, sweep, boarfish and Port Jackson sharks, with southern rock lobster in the holes and, since protection, on the open reef, weedy seadragons along the weed lines and rays on the sand. Because it is shallow and extensive it is a long, relaxed dive rather than a deep one, well suited to open-water divers from a club boat on a calm day, and a good place to look for wreck iron without any of the hazards of a wreck. Its difficulty is entirely logistical: it is a Bass Strait reef with no lee, the Anglesea ramp is small and bar-affected, no charter runs it regularly, and coordinates are not published by the usual directories, so it is dived by locals with the marks and by clubs on settled autumn days.

Jarosite Reef, closer inshore, is the snorkelling equivalent.

Boat dive. Launch at the Anglesea boat ramp inside the river mouth (small, tide- and bar-dependent) or at Point Roadknight, or at Torquay's Fishermans Beach ramp, and run 3-8 km to the reef, 15-30 minutes depending on the ramp; charters occasionally come from Queenscliff on flat days as a long run west. The reef is a broad shallow platform with many possible anchorages; anchor on sand in a gap, not on the reef, as it is within the marine national park.

Not a shore dive.

Open Bass Strait reef with no shelter: needs a swell under about 1 m and light winds, ideally northerly, because the reef top is shallow enough for swell to break over it and surge through it. Autumn and early winter give the most days. Visibility ranges from 5 m after weather to 15 m or more on clean water; 8 m is typical.

Small boats need to watch the Anglesea bar and afternoon sea breezes. Whales pass along this coast May to September.

Anchor on sand in a gap, descend to 8-10 m and work across the reef platform through the kelp, following gutters and ledges, looking for scattered iron from the Inverlochy and for crays walking in the open, keep a compass bearing back to the anchor, turn at half gas and ascend the line with a 3-minute stop.

No regular operator – private boats and dive clubs (Geelong and Melbourne club boats on calm days); Dive Victoria Group and Scubabo Dive Victoria (Queenscliff) run occasional Surf Coast trips west of the Heads in settled weather.