The Sponge Garden Drift is the gentle introduction to the Heads drift dives that Queenscliff operators run inside Port Phillip when the ebb is running: a live-drop drift over the sponge beds south of the pier that lets divers experience the tidal current without the depth and exposure of the Rip itself. The Scuba Doctor describes it as taking you over massive sponge gardens and shallow reefs inside Port Phillip, and says it is the colours of the sponges that make the dive stunning, which is exactly right. The tidal flow through the Heads delivers plankton on every tide and the seabed here is carpeted with filter feeders in a density found nowhere else in the bay: finger, cup, fan and encrusting sponges in orange, yellow, red and purple, sea tulips, ascidians, bryozoans, gorgonian fans and soft corals on the harder ground.

The dive passes through three zones as the stream carries you south: low shallow reef at 12 m, then the open sponge gardens at 14-16 m, then larger reef formations and bommies to 20 m near Torpedo Reef. Fish are variable, as they are on all drifts, but old wives, magpie perch, boarfish, leatherjackets, blue-throat wrasse, sweep and the occasional blue devil, seadragon or seal are all seen, and old bottles and other relics of Queenscliff's shipping history litter the sand between the sponges. Because it is inside the Heads it is sheltered from swell and is the operators' fallback when the outside sites are too rough.

It suits advanced or experienced open-water divers who are comfortable with drift procedures and a surface marker, and it is often the second dive of a Heads day after a wall or wreck. Jane Headley's video Sponge Hollows shows it well.

Boat dive only, run from Queenscliff Harbour by the local charter operators (Dive Victoria Group, Scubabo Dive Victoria, Bay City Scuba's boat) as a 5-10 minute trip from the harbour, or by private boat from the Queenscliff ramp. The dive is done as a live drop on the ebb tide with the boat following the divers' surface marker; it is not a shore dive and not an anchored dive. Book as part of a Heads double-dive day; operators schedule it to the tide.

An ebb-tide-only drift: the dive runs on the outgoing stream and is scheduled by the operator to the Port Phillip Heads tide tables, usually an hour or two after high water. Being inside the Heads it is sheltered from ocean swell and diveable in most winds up to about 20 knots, though strong northerlies make the pick-up uncomfortable. Visibility is typically 8-15 m and best in autumn and winter when Bass Strait water is clearest; big spring ebbs run fast and reduce bottom time.

Surface marker buoys are mandatory because of shipping and ferry traffic through the Heads.

Live drop at the start of the ebb, descend quickly as a group to the shallow reef at 12 m, deploy the SMB and drift with the stream over the sponge gardens at 14-16 m, then onto the larger reef formations and bommies at up to 20 m, hold depth off the bottom to avoid damaging sponges, ascend as a group with a 3-minute stop at 5 m under the marker and let the boat pick you up.

Dive Victoria Group (Queenscliff) – regular ebb-tide drift on Heads double-dive days; Scubabo Dive Victoria and Bay City Scuba (Geelong) charters also run it when the tide suits. Ebb tide only.