They criticised their decision not to adopt the EU's traffic light system by taking Italy and Greece from the green list when both countries have Covid rates 60 per cent less than Ireland.
They are also classified under the new EU system as having no travel restrictions within the EU, according to the airline.
Ryanair's statement comes as seven countries made it onto Ireland's updated travel green list today.
People can now travel to Cyprus, Finland, Germany, Iceland, Latvia, Lithuania and Poland from Monday without having to self-isolate for 14-days when they return to Ireland.
Ryanair called it a "nonsensical decision" by the government to remove both countries and who continue to ignore the report of the Aviation Task Force, which has been on Minister Ryan’s desk for over for over 2 months.
A Ryanair Spokesperson said this evening:
“Today’s announcement shows that the left hand of the government doesn’t know what its right hand is doing.
"There is no scientific basis behind the decision by Minister for Foreign Affairs Simon Coveney to remove Italy and Greece from the Green list only to add them back again in 3 weeks’ time.
"Over 140,000 people are directly / indirectly employed in aviation with a further 325,000 employed in tourism who depend on the aviation sector, and this continual, disjointed and mismanaged approach is putting all of these jobs at risk."
The spokesperson said Ryanair is now calling on the government to immediately put in place the EU traffic light system that would see 21 EU countries including Italy and Greece, not requiring any restrictions.