All Irish airports have reopened until further notice after volcanic ash grounded flights yesterday and this morning.
The Irish Aviation Authority said it did not expect to restrict Irish airspace for at least the next 48 hours.
The authority said the ash cloud is now moving east away from Irish airspace.
Restrictions at Heathrow and Gatwick airports have also been lifted.
From 1pm to 7pm today, the no-fly zone remains in place in the Orkney and Shetland Islands, but restrictions have been lifted at all other UK airports.
Airports in Amsterdam and Rotterdam have also reopened.
Passengers intending to fly over the coming days are advised to check airline websites before going to the airport.
In a statement issued tonight, the IAA said that revised safety zones agreed by aviation authorities, airlines and aircraft manufacturers are to be introduced from midday tomorrow.
The new zones are expected to reduce flight restrictions.
The new approach consists of a new three-zone safety area that comprises an inner no fly zone, a time limited zone and an enhanced procedures zone.
Aircraft with approved certification can now operate in the time limited zone with the approval of their regulatory authorities and engine and airframe manufacturers.
