The airline is axing all domestic flights to or from Bergamo, Malpensa, Parma and Treviso from 10 March as the Italian government closes all schools, gyms, museums and nightclubs.
Up to 16 million people in northern Italy need special permission to travel under the new isolation rules.
Additionally, from 12 March, any international route into the country which normally operates multiple times a day will be reduced to one flight per day on Fridays, Saturdays, Sundays and Mondays, such as from Stansted to Malpensa.
The changes are currently scheduled to be in place until 8 April.
Anyone who has been affected has been notified of the change, Ryanair said.
A spokesperson from the airline apologised for the disruption.
