The low-cost Irish airline which predicted that 100,000 passengers would be affected, said in a statement they had “been offered re-accommodation on alternative flights” or a complete refund.
Cabin crew in Italy are also striking but a spokesman for the airline said this was not expected to affect the “Italian-based schedule”.
Unions in all four countries are asking that Ryanair staff be employed according to the national legislation of the country they operate in, rather than that of Ireland as is currently the case.
They also want the airline to give contractors the same work conditions as its own employees.
“These strikes are entirely unjustified and will achieve nothing other than to disrupt family holidays, and benefit competitor airlines in Belgium, Portugal and Spain,” Ryanair's chief marketing officer Kenny Jacobs hit back in the statement.
“Ryanair cabin crew enjoy great pay — up to 40,000 euros ($47,000) p.a. (in countries with high youth unemployment) — industry leading rosters (14 days off each month), great sales commissions, uniform allowances and sick pay,” he added.
Ryanair staff are also demanding that the airline recognise unions for pilots and cabin crew and that it negotiate with a representative chosen by these unions and not the company.
So far, the airline has only recognised cabin crew and pilots' unions in Britain and Italy.
In a statement, it said it was “engaged in extensive negotiations with national cabin crew unions across Europe”.
The strike will come two weeks after a work stoppage by Irish Ryanair pilots that saw some 30 flights cancelled.