Dublin Airport is set to remain closed until at least 8pm this evening and has asked passengers whose flights have been cancelled to leave the building because of what is calls "severe congestion".
Flights at Cork, Shannon and Knock are running, but delays are expected. All Irish Rail services are running, but again with delays.
Curtailments are in place on some Dublin Bus routes. Customers are being advised to check their website for updates.
Meanwhile, Luas services are running as normal.
Air passengers across the UK are also facing major disruption as are people in Germany, France and the Netherlands.
Hundreds of flights were cancelled from Frankfurt yesterday after fresh snowfalls. Amsterdam's Schiphol airport was also hit.
Staff at Charles de Gaulle and Orly airports, near Paris, are still working to clear the backlog today.