The vehicle travelled 4084 km across the desert from Perth to Sydney over nine days in a test of the experimental vehicle's durability.
"We could have done it in four days but we didn't want to take any chances, we wanted to show this could be done," organiser Hans Tholstrup said.
Named Apollondine after mythical ancient Greek sun and water gods, the vehicle was built by students at Tamagawa University in Tokyo.
The car's exhaust emissions consist of pure water, which Sydney Lord mayor Lucy Turnbull drank from a glass after it arrived in Sydney.
Tholstrup, who pioneered solar-power car races in Australia 20 years ago, said the journey showed alternatives to the traditional internal combusion engine could be developed.
"If you're asking when this technology could be commercially viable, then the answer is 'how long is a piece of string?'," he said.
"When oil hits 60 dollars a barrel then it will be viable. It could be 70 or 80 US dollars but sooner or later people will use these building blocks we are creating.
"It's interesting that clever university students have come up with this design, instead of the major car companies."