Australian driver's licence holders can freely drive throughout Greece without requiring an international driving permit.
The measure came into force on 5 November 2021.
Previously, Australian tourists and residents could drive in Greece for an unlimited period if they had a valid Australian driving licence and a valid International Driving Permit issued by the State/Territory in which the driving licence was issued. That permit is no longer needed.
Meanwhile, according to the Australian Embassy website, Australian driver's licence holders who wish to convert their Australian licence to a Greek one can apply to a local transport office of the Greek Ministry of Transport (210 650-8000).
No driving test is required. We suggest you contact the Greek Embassy/Consulate in Australia, which may also assist in this procedure.
AN INTERNATIONAL PERMIT IS STILL REQUIRED FOR US CITIZENS
The US State Dept country information for Greece, which states in the Travel and Transportation section:
“Short-term Car Rentals: Greek law requires that visitors carry a valid U.S. driver’s license and an international driver’s permit (IDP), even if the rental company does not request to see your IDP.”
Note that the law is for driving in Greece, not for renting a vehicle. I think, for this summer, since the change hasn’t been widely publicised, it would be a good idea to have an IDP if you plan to drive in Greece.
The IDP issued by AAA in the USA is still listed on their website as costing only $20.