Representatives from the airline and union leaders from USO and Sitcpla failed to produce an agreement after talks lasting seven hours on Tuesday.
The budget airline confirmed its plans to close down its bases in Gran Canaria and Tenerife and is still considering whether to close operations at its base in Girona.
Unions estimate that the closures could lead to the loss of 350 cabin crew jobs and 150 pilots.
The SITCPLA and USO workers' unions said in a statement on Wednesday that they planned to formally lodge notice of strikes unless Ryanair makes concessions in the coming days.
En Septiembre convocamos 10 días de huelga en todas las bases de España en @Ryanair_ES . Tenemos que impedir el cierre previsto de las bases de Gran Canaria, Tenerife Sur y Girona, que hasta ahora segun ellos eran las bases más rentables de la compañía.. NO CUELA!#HuelgaRyanair pic.twitter.com/y1r0pFWXCg
— USO-Canarias (@USOCANARIAS) August 14, 2019
The strikes are planned for September 1st and 2nd, as well as the 6th, 8th, 13th, 15th, 20th, 22nd, 27th and 28th and could affect hundreds of flights not only in Spain but also across Europe.