Seepferdchencam
Registered
Yup. <looks at map> "Oh, I'll just drive from Melbourne to Sydney today, no worries." Yeah, right.
That's one trip you can do in a day as it's all freeway and easy albeit boring driving.
If you're considering Melbourne the boats you want to investigate are Scubabo, Bay City Charters, and Chimney Rock Charters. There is a dive site guide here.
There is a lot of shore and pier diving. The most popular pier dives are Blairgowrie, Rye, and Flinders. You will need a car.
In terms of buddies your best bet will be the "Scuba dive Melbourne" and "Dive Buddies Social Group" Facebook groups.
This will give you some idea of water temperature. Visibility often better in winter.
Standard rental tank is a steel 12.2l with a din/k valve.