EE creates 300 jobs at Merthyr Tydfil, Darlington and Tyneside
Up to 200 jobs are being created by mobile phone company EE at its call centre in south Wales with another 100 in north east England.
Customer services and sales jobs will be based at Merthyr Tydfil as well as Darlington and North Tyneside.
A total of 15 apprenticeships are also being offered in south Wales in a link up with College Merthyr Tydfil.
Merthyr Tydfil and Rhymney MP Dai Havard said the decision was a "vote of confidence" in the local community.
BBC Wales Today's Nick Palit reports.