Port Phillip Heads, VIC
Lonsdale Wall lies inside Point Lonsdale on the western edge of the Port Phillip Heads channel. Every tide change funnels the bay's water through the narrow entrance, and the wall sits in the path of that flow: vertical sponge and sea-fan growth from 12 metres past 30, with overhangs, swim-throughs and a deeper rubble slope continuing to 40 metres. Dives only run during the 30-minute slack windows either side of high or low water, set by the tide tables for the Heads. Operators in Queenscliff, Sorrento and Portsea time the boat run for the slack window. Outside the window the current is dangerous. The wall produces Victoria's richest sponge-garden cover and reliable big-fish encounters in the deeper sections.