The Irish Aviation Authority has said Dublin Airport will remain closed until at least midday tomorrow because of the volcanic ash cloud.
Cork, Shannon and Kerry airports all remain open, while Sligo and Knock airports will re-open at 9am. Waterford and Galway airports will both re-open at 6am.
Donegal airport will remain closed until at least 12pm.
North Atlantic overflights through Irish-controlled airspace remain unaffected.
The IAA said: 'The volcano's activity and the latest weather forecasts indicate an increased quantity of ash over Irish airspace.'
IAA Chief Executive Eamonn Brennan confirmed the closure of Dublin Airport on RTÉ Radio this afternoon.
Mr Brennan said it was becoming more difficult to predict the impact of the volcanic ash because the eruptions are more periodic.
However, he said he the outlook for later tomorrow looks better and he is reasonably optimistic for later in the week.
Aer Lingus, Ryanair and Aer Arann have cancelled a number of services as a result of the airport closures.
All Aer Lingus flights with a scheduled departure time up to 12pm tomorrow are cancelled, including Aer Lingus transatlantic flights EI 105 from Dublin to New York and EI 133 from Dublin and Shannon to Boston.
Aer Lingus flight EI 124 from Chicago to Dublin will be diverted to Shannon airport and a coach transfer will be provided for Dublin-bound passengers
The IAA will issue a further update at 9.30am tomorrow.
The British Civil Aviation Authority's no-fly zone will be extended south to include London's Heathrow and Gatwick airports from 1am.
Earlier Nats extended its no-fly zone south to include airports in Birmingham and Norwich.
Restrictions at Belfast International Airport and Belfast City Airport will until at least 7am. Restrictions at City of Derry airport will continue until 1am.
Manchester, Liverpool, East Midlands and Prestwick are among other UK airports to close. The restrictions will remain in place until at least 1am tomorrow.
Virgins Trains has said there will be some longer trains tomorrow on the line between London and Holyhead to connect with ferries to Dublin.
The spread of ash from the erupting volcano under the Eyjafjallajokull glacier in Iceland grounded much of European air traffic for nearly a week in mid-April.
Airlines had to cancel around 100,000 flights, stranding millions of passengers.
Airport Flight Operations:
Dublin - Closed from 7pm until at least 12pm tomorrow
Cork - Open until further notice
Shannon - Open until further notice
Donegal - Closed until 12pm tomorrow
Sligo - Re-opens at 9am tomorrow
Ireland West (Knock) - Re-opens at 9am tomorrow
Galway - Re-opens at 6am tomorrow
Kerry - Open until further notice
Waterford - Closed from 11pm until at least 9am tomorrow