Donegal, Sligo, Ireland West (Knock), Galway and Kerry on the west coast will reopen at 6:00 am (1030IST) the Irish Aviation Authority (IAA) said.
They were closed progressively Sunday due to the threat to plane engines from an ash cloud hovering over the Atlantic.
"The past number of days has seen the growth of a large cloud of high ash concentration off the west coast of Ireland, and this has caused difficulty for some transatlantic operations," said the IAA in a statement.
The air safety watchdog added it was "monitoring the path of the ash cloud", which was around 3,400 kilometres long and 2,240 kms wide.
Restrictions were also lifted late Sunday in Scottish airspace - they had been imposed over some northern areas - with the exception of the island of Barra in the Outer Hebrides.
Ireland has faced several fresh shutdowns in recent days. On Thursday airports were closed before being re-opened just three hours later.
Europe's skies were shut for up to a week last month following the eruption of Iceland's Eyjafjoell volcano. It was the biggest shutdown of airspace in Europe since World War II.
Volcanic ash can cause serious damage to jet engines.
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