Ryanair must indicate the full price of the ticket when it displays offers on its website, the EU's top court said on Thursday.
The Court of Justice of the European Union (CJEU) made its ruling after the Italian antitrust authority (AGCM) criticised Ryanair in 2011 for prices that did not include value-added tax on domestic flights and fees for check-in and payments by credit card.
The AGCM argued these were unavoidable and should be indicated before a customer began the booking process. Ryanair took the matter to court, prompting Italy's Council of State to ask the CJEU whether the price elements needed to be included.
The judges in Luxembourg said Ryanair had to show in its initial offer unavoidable and foreseeable taxes, surcharges and fees. Optional price supplements could be left until the start of the booking process, they said.
They found that fees for using a credit card were unavoidable and should be shown in the initial offer.
Check-in fees also needed to be shown unless there was at least one option to check in free of charge.
Value-added tax applied to the air fare should also be included, although did not have to be included for optional supplements, the judges said.
Ryanair representatives were not immediately available for comment on the ruling.