At least 85 jobs are being lost in the city.
160 roles are being axed at Three Ireland as part of its takeover of O2.
75 of those jobs are at the company's head office in the city centre -
And 85 staff who work in retail will also be let go.
It also says it won't be extending the contracts of a number of staff when they expire.
In a statement, the company says the cuts follow an extensive planning and consultation process that is ongoing with employees.
Meanwhile, Three says 90 new customer care roles will be created in Limerick over next 12 months.
Three also says 25 IT and Network jobs have been created in Dublin over the past year
