The Irish Aviation Authority (IAA) said Irish airspace will reopen today after two days of closure as the current ash cloud moves southwest.
The IAA lifted restrictions following the latest advice from the Volcanic Ash Advisory Centre in London and Eurocontrol.
Dublin, Waterford, Donegal and Cork airports will operate today from 4am IST.
Flight operations will begin from 6am at Sligo airport, 8am at Galway, Knock and Shannon airports, and 9am at Kerry airport.
Overnight flights will be allowed in Irish airspace between North America and Europe as usual.
Ryanair will operate all flights to and from Dublin, Cork, Knock and UK airports on schedule today.
A government task force on emergency planning will hold a meeting today to discuss the continuing impact of the Icelandic volcanic ash cloud on Irish aviation.