Ryanair will "reluctantly" allow parents to sit with their children for free, a change it said would be revenue-neutral and comes two weeks after Britain's competition watchdog launched a probe into its policy.
Europe's largest airline by passenger numbers previously required adults travelling with children aged between 2 and 11 to pay a "family seat" charge, allowing up to four children to sit next to one accompanying adult.
Ryanair changed its family seating policy after an investigation by the Competition and Markets Authority (CMA) into its practice of charging parents to sit with their children.
From Thursday, parents who do not select or pay for reserved seating will be allocated seats free of charge after check-in.
Families choosing this option have been told they are likely to be seated near the back of the aircraft, as front-row seats are reserved and tend to sell out.
Those who wish to choose their seats in advance can still do so by paying a fee.
Ryanair CEO Michael O'Leary was pointed in his response to the regulatory pressure.
"We will reluctantly adjust to this industry standard, as we don't want to waste time explaining to misguided regulators how badly they misunderstand what is in the best interests of UK and European consumers," he told reporters.
He added: "Under our revised family seating policy, families may have to wait until after they have checked in to find out their seat allocation and are more likely to be seated at the rear of the cabin, but at least the CMA will be able to claim they have done something for consumers. Sadly, most consumers won't notice."
The CMA launched its investigation into the budget airline two weeks ago over a per-flight charge of $10, examining whether the policy constitutes an unfair contract term under consumer law.
Ryanair, for its part, maintained it "does not charge any fee for children to sit beside their parent or accompanying adult", adding:
"Like all adults who select a reserved seat, adults travelling with children pay one reserved seat fee but can select reserved seats beside them for up to four children on the same booking free of charge."
