In his ruling against Jetstar, Federal Court Judge Lindsay Foster said he was of the view a penalty of A$295,000 for the website conduct was appropriate and a penalty of A$250,000 for the mobile site conduct was in order.
"I regard the website conduct as more serious than the mobile site conduct, essentially because the website is used by consumers far more often than the mobile site in order to make bookings with Jetstar," said Justice Foster.
"These penalties are fixed at the lower end of the scale when regard is had to the maximum penalty that may be imposed in each case."
Both airlines have since addressed the issue of credit card fees, disclosing the charges upfront in the booking process.
ACCC Chairman Rod Sims said it was pleasing to see the courts taking this issue seriously and imposing appropriate penalties.
"I think it's fair to say the penalty reflects the amount of consumer angst out there," Mr Sims said.
"If you raise this topic a lot of people get very angry. They get right through the (airfare) booking process thinking they're going to pay one price only to be hit with extra charges at the end.
"I'm surprised companies treat their customers this way."
Under the Australian Consumer Law, Virgin Australia and Jetstar could have faced a maximum penalty of $1.1 million for each offence.
A Jetstar spokeswoman said they accepted the court's decision.
"We want our booking process to be clear for our customers," said the spokeswoman.
"That's why we made changes to our web and mobile sites to make the options available and fees that apply even clearer. These changes, made in 2014 were previously found to be satisfactory by the Federal Court."
