The service cost the equivalent of $61,000 and patronage was 63 per cent higher than a normal weekend.
It was part of World Car Free Day on Sunday.
The Diamond Harbour Ferry had more than 800 people taking the ferry each day.
But the popularity of the service came with a two hour wait time to board the ferry.
This caused delays and inconveniences for some passengers, said ECan senior manager public transport Stewart Gibbon.
"Black Cat, the ferry operator, did an outstanding job, with extra trips run on Sunday to accommodate the demand," he said.
Funding for the free services came from ECan's existing marketing and promotions budget.
"Public transport is funded from a combination of fares, rates and central government grants," Mr Gibbon said.
World Car Free Day is a global event focused on encouraging more sustainable travel choices and reducing harmful emissions by leaving the car at home.
Last year, free public transport was only offered by ECan on one day, September 22, for World Car Free Day.
In one day, there were more than 15,600 additional trips across the network, a 60 per cent increase from a normal Saturday.
