EE has opted for Londonderry in Northern Ireland as the location of its new UK customer service centre.
The new site will be managed by Convergys and is set to open in late Spring with recruitment for the new roles to begin shortly.
In February this year EE set out plans for a jobs drive that will see over 1,000 customer service jobs brought back to the UK from overseas call centres.
The opening of the new customer service centre in Northern Ireland will provide a boost for employment in Northern Ireland.
The location of the remaining roles for the UK will be announced in due course.
Olaf Swantee, EE CEO, said: "Returning over 1,000 customer jobs to the UK from overseas call centres is a significant part of the strategy to achieve this goal."
Arlene Foster MLA, Minister of Enterprise, Trade and Investment, added: "Following the Invest in NI conference chaired by the Prime Minister and the First Minister last autumn I am delighted that EE, along with their partner Convergys, have announced that they will be opening their newest customer service centre in Londonderry and bringing 300 jobs to Northern Ireland.
"This shows that Northern Ireland workforce can compete and win on the quality of service they offer."