The Point Lonsdale Kelp Forest is a strip of dense kelp along the edge of Shark Gutter, the main channel through the limestone platform beneath Point Lonsdale lighthouse, at the western jaw of The Rip. The Scuba Doctor listing puts it at 3–5 m and describes the forest as growing 'along the edge of Shark Gutter' and extending 'around towards the Lonsdale Jetty'; it adds that 'currents can eddy through and around the area at peak tide flows' and that calm conditions are essential.

The kelp is a mix of Ecklonia and, on the outer edge, bull kelp, growing on a platform of ledges and gutters that is scoured twice a day by the tide. Under the canopy the light is green and low and the fauna is that of a high-energy southern reef: southern rock lobster in the gutter walls, abalone on the rock, big bluethroat wrasse, moonlighters, scalyfin, magpie morwong and, on the sand patches in the gutter, weedy seadragons. Juvenile western blue groper – rare this far east – have been recorded on the adjoining Point Lonsdale Light site. The wrecks of the George Roper and Holyhead lie on the outer reef a few hundred metres to the south-west and Buckley's Cave, the escaped convict William Buckley's shelter, is on the shore above.

This is a dive for experienced shore divers who can read the Heads tide. The whole site is inside the tidal race: the ebb slack gives a short window, the flood arrives as a river over the reef, and the surge in the gutters is constant. On the right day – a dead-calm morning at the end of the ebb – it is an atmospheric, clear-water kelp dive within sight of the lighthouse and one of the few Heads dives that costs nothing but a tide table; on any other day it is dangerous.

Drive to Point Lonsdale (30 minutes from Geelong via the Bellarine Highway, about 90 minutes from Melbourne) and follow Point Lonsdale Road to the lighthouse car park at the end of the road; free parking, toilet block by the lighthouse, and the water is 50–150 m away. Take the path from the car park past Buckley's Cave down to the rock platform below the lighthouse. The platform is sharp, gutter-cut limestone that is only walkable around low water, so time the walk for the bottom of the tide and carry gear in one trip; entry is straight off the platform into the gutter and the exit is the same way, before the flood makes up over the reef.

Nearest air: Dive Victoria Group at Queenscliff Harbour (5 km). Melway 499 J6, beach marker 1B.

Shore dives on the Point Lonsdale platform are only possible at slack water at the end of the ebb, in the 20–40 minute window before the flood begins to pour in over the reef; the Point Lonsdale Light listing warns 'do not attempt this dive with the incoming tide washing in over the Point Lonsdale Reef, as you will be easily swept away'. 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.

The platform faces the Rip and Bass Strait: it needs a swell under about 1 m and no southerly or westerly wind – in practice a few days of northerlies or a dead-calm morning – and even then surge runs through the gutters. Winter brings 11–13 °C water and bigger swells; late summer and autumn give most of the workable days. Visibility on the platform is usually clear (5–15 m) because the water is straight from Bass Strait.

Enter the gutter from the platform at the end of the ebb, swim out along Shark Gutter with the kelp wall on one side, and work the edge of the forest at 3–5 m northward toward the jetty; turn after 15–20 minutes or at the first sign of the flood and come back along the gutter to the entry point. Tow a float and flag.

No commercial operator runs these shore dives; Dive Victoria Group (Queenscliff) can advise on conditions and occasionally guides the platform for experienced groups. Dived independently by Bellarine and Geelong club divers on the rare calm ebb slacks.