Online bookings and check-ins with Ryanair will close for 12 hours after the airline said it needed to shut down its website and mobile phone app.
The shutdown will take place from 5pm UK time (6pm in Malta) to 5am UK time (6am in Malta).
Ryanair "sincerely apologised" to customers for any inconvenience, and urged anyone needing to check in to do so before the closure. The carrier's online check-in facility is open between 48 hours and two hours before a flight for passengers who have not paid extra to select a seat. Passengers who need to check in at the airport have to pay a few of around €60.
There are about 1.5 million visits to Ryanair’s website every day, with 22,700 boarding passes downloaded each day.
This week, Ryanair reported an 11 per cent rise in traffic in October, as it carried 13.1 million passengers. The airline had to cancel about 300 flights this month, due to a combination of an airport handler strike at Brussels Zaventem, bad weather, and continuing air traffic control staff shortages in the UK, Germany and France.