Irish Ferries has cancelled a number of crossings between Dublin and Holyhead this Friday because of 'adverse weather conditions for the Irish Sea'.
The 'Swift' and 'Oscar Wilde' services are affected, but the company says customers will be accommodated on other ferries during December 23rd and 24th.
It comes as Met Éireann has issued two weather warnings for Friday, with Storm Barbara set to pass over Ireland this weekend.
Meanwhile in the UK - Heathrow Airport says some arrivals are delayed this morning because of thick fog.
It is expected to be heavy until around 9am, and will then ease off.
So far no departures have been cancelled - but passengers are being advised to check before travelling.