Ryanair pilots based in the Republic of Ireland have voted for strike action.
Of the members of the Irish Air Line Pilots’ Association (IALPA) who voted, 94% were in favour.
IALPA said the decision reflected the frustration and disappointment of pilots with a lack of progress in ongoing pay talks.
UK-based pilots voted for strike action on Wednesday, while pilots in Spain will vote on strike action in the coming days.
UK pilots have announced two walkouts, one from 22-23 August and another from 2-4 September. No date has been set for the possible Irish action.
RTÉ reported that the union will inform managers of strike plans early next week unless the airline agreed to union pay proposals by Monday.
Ryanair said fewer than half of its Irish pilots are members of the union and fewer than 60% of members took part in the vote.
The airline was hit with a series of strikes last summer as talks over contracts and pay failed to reach agreement.
The airline has also announced it may need to cut up to 1,500 jobs following delays in the delivery of new aircraft.