Airbnb has been fined $15 million for failing to indicate its accommodation prices were listed in US rather than Australian dollars and faces a compensation bill of the same amount.
Between January 1, 2018 and August 30, 2021, Airbnb Ireland UC displayed to 63,000 Australian customers the total price for Australian accommodation with only a dollar sign.
It did not indicate whether the price was in Australian or US dollars, with customers only finding out it was in USD when they reached the check-out page.
More than 2000 consumers complained to Airbnb but the company said they had selected to pay in USD even when they had not done so.
Federal Court Justice Brendan McElwaine on Wednesday found the conduct was misleading or deceptive or likely to mislead or deceive.
"The affected users ... suffered damage in several ways," he said in his written judgment.
"They were deprived of the opportunity of making an informed choice of accommodation.
"All prices displayed in USD appeared lower than if they had been displayed in AUD.
"Thus, the relevant users paid more than they expected to pay for the accommodation selected."
Judge McElwaine ordered Airbnb pay a $15 million penalty to the Commonwealth of Australia within 30 days, as well as $400,000 in costs.
Airbnb provided an undertaking to the court that it would provide compensation to eligible customers, which could total another $15 million.
The company must implement a consumer law compliance program, which will feature a new complaints-handling system and more staff training.
Airbnb's Australia and New Zealand country manager Susan Wheeldon said ensuring consumers could book with confidence was the company's priority.
"While only a very small percentage of Australian guests are believed to have been impacted, we are disappointed that this happened," she told AAP in a statement.
"Airbnb would like to apologise to those guests."
Ms Wheeldon said the company was committed to price transparency and it would continue to find ways to improve systems so guests and hosts could enjoy travel.
The chair of the Australian Competition and Consumer Commission said the judgment sent a strong message to large digital platforms that they needed to follow Australian laws.
"We are pleased with the undertaking by Airbnb to pay compensation, which provides a meaningful outcome for the affected consumers," Gina Cass-Gottlieb said.
"Eligible consumers will be contacted by Airbnb within the next 45 days and invited to lodge a claim, but they can also contact Airbnb to ask about their claim if they think they are eligible."