Port Phillip · Australia · Wall · Cave & cavern
The Grotto
Small caves and big overhangs on top of the Lonsdale Wall
Area photo: Kgbo · CC BY-SA 4.0
The Grotto sits on top of the Lonsdale Wall system and takes its name from the many small caves and large overhangs that form it. The ground increases gradually to around twenty-three metres through a run of rock formations, and the cut-back structure and the shelter it gives are why divers come here with a camera.
Where it is and how deep
38.2777° S, 144.6370° EPublished position for this site.
The dive
Depth comes on gently here. The ground slopes rather than drops, working down to around twenty-three metres, so this is a traverse through rock formations instead of a wall profile. The caves are small, and the overhangs are the larger feature: sheets of rock cut back over the ground with open space underneath them.
That structure is why the site is rated for photography. Blue devil fish, leather jackets and crayfish hold under the overhangs, and the rock carries nudibranchs, mosaic sea stars and yellow sea spiders for anyone working close. A profile that never gets deep leaves enough bottom time to work a single formation properly instead of passing it, and the route is simply the next hole along, so navigation comes down to keeping the rock on one shoulder. Like the rest of the wall system, it is dived on the slack.
Marine life and season
- Nudibranchs
- Macro critters
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Good | Good | Good | Good | Prime | Prime | Prime | Good | Good | Good | Good | Good |
Season follows Port Phillip: The spider crab aggregation runs May–Jul; winter also brings the clearest water, while summer is warmest but greener.
Sources
- The Grotto — Scubago/SSI
More dive sites in Port Phillip
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Pinnacle
A 200 m rock circled in one dive, 18 m sand to 12 m top
Ledges and swim-throughs in 6-9 m, straight off the car park
Wall
A broken wall from 12 m to 30 m, cut with overhangs
A 138 m guided missile frigate sunk at 30 m
Wall
The shallow 8 m top of the Lonsdale wall system
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