The Three telecommunications and data company is to expand its customer contact centre in Limerick, taking on an additional 175 employees there over the next four years.
The new jobs will bring the company's workforce at its Castletroy plant to 570.
Three is the country's largest telecommunications provider, with over 3 million customers.
Its base in Limerick was established 20 years ago and it has now announced plans to expand the current 400 staff count there by another 175.
The contact centre in Limerick is already providing support to business customers here. Tthe expansion will allow it, for the first time, to provide those business solutions, supports, ICT products and cost management services to its growing UK business market.
The jobs will be full and part time positions in customer care and operations, while the company will also recruit team leaders and managers.
Three's chief executive Robert Finnegan said the expansion of the company's operations at the Limerick Customer Experience centre demonstrates the strength of its customer service in Ireland.
He said the company was excited to build on the high standard of talent they have.
The expansion has been welcomed by Tánaiste and Enterprise Trade and Employment Minister Leo Varadkar, who said it further strengthens the company's presence and commitment to Limerick and the staff at Castletroy.
IDA CEO Martin Shanahan said the expansion is terrific news for the Mid West and demonstrates Three's confidence in its ability to service international clients from Limerick.
Three employs 1,300 people in Ireland across its business and customer care service centres in Dublin and Limerick and across 60 retail stores.
It is owned by the multinational technology and innovation company CK Hutchison, which employs 300,000 people across the world in four core businesses - ports, retail, infrastructure and telecommunications.