Holyhead Port won't reopen until at least January 15th.
The facility's operator Stena Line says all ferry services to and from Dublin are cancelled until this time.
It says passengers booked to travel from December 20th can transfer free of charge to an alternative route run by the shipping company.
In a statement Stena Line says: "It has been announced that Holyhead Port will not be reopening for ferry services until at least 15 January 2025.
"Stena Line has been working hard to provide alternative travel arrangements for customers during the busy festive period. Customers are currently being contacted and affected passengers are advised to amend their booking online free of charge or through the Contact Centre on 0344 770 7070 (UK)/ + 353 1 907 5555 (ROI).
"Stena Line is offering sailings for passengers and freight from Dublin to ports in Birkenhead and Fishguard. In addition, a new freight route from Dublin to Heysham has been added to assist continuity of trade flows. The company has also added additional sailings on the Belfast – Cairnryan route this weekend. Currently there is limited availability on the Belfast – Liverpool and Rosslare – Fishguard routes.
"Stena Line would like to apologise for the inconvenience caused and assure customers that the company is doing everything in its power to mitigate the effects of the closure on passenger and freight traffic."
