Aer Arann is suspending services from Southend, Luton, Manchester, Edinburgh and Waterford to Galway airport from 31 October.
Bookings have deteriorated meaning the airline’s routes from Galway would be loss-making during the winter.
The airline admitted some redundancies may arise if staff are unable to relocate, although staff will also be offered unpaid leave through the winter.
"We sincerely regret having to make this decision and we particularly regret the impact that this will have on our customers, on our staff in Aer Arann Regional and on the staff of Galway Airport," said chief executive Paul Schütz.
Passengers with confirmed booking for flights after these dates will be contacted directly by Aer Arann about their travel options.
Booked passengers on all routes will be offered a full refund but passengers on the Manchester and Edinburgh routes will have a re-booking option on Aer Lingus Regional flights operated by Aer Arann from other airports.
Passengers booked from Manchester will have the option to travel instead via Shannon and those from Edinburgh will have the option to travel instead via Shannon or Dublin.
By Diane Evans
