Cornwall Council has awarded a £14m outsourcing deal to BT, which is set to be finalised next week, after some minor changes.
Circa 300 staff will TUPE from the council to the joint venture with BT.
BT will deliver savings of £17.6m over a 10-year contract, and will create 510 new jobs in Cornwall.
Council leader Jim Currie said: “This proposal has been subject to a great deal of discussion and the contract has been thoroughly examined. As a result, all the partners are confident that the offer can be delivered, and we all now need to work together to achieve this."