A call centre has announced 350 new jobs in Swansea while a decision is due on the creation of 300 others in Cardiff.
118UK is to open premises in Orchard Street and will start recruiting at the weekend.
The firm's major expansion is in response to the government's deregulation of the 192 national and 153 international directory inquiry services in the UK
The firm already employs 500 people in Cardiff and has said there is a possibility a further 350 jobs could be created in the Welsh capital.
Wednesday's announcement comes as the BBC's Eye on Wales has revealed other call centre operators are facing problems.
Research commissioned in part by the Welsh Development Agency (WDA) has predicted 40% of call centres across Wales will have disappeared by 2005.
118UK general manager Neil Evans said Swansea had been chosen following a nationwide search for a suitable location.
"Swansea is an attractive location for us because of the quality of the employees available to us, and the availability of offices close to public transport facilities," he said.
An open day will be held at Swansea's High Street Job Centre on 1 March for potential employees.
Swansea cabinet member for development Byron Owen said it was a credit to the city's workforce that Swansea had been chosen.
"We are delighted to hear of this announcement regarding the creation of 350 permanent jobs in Swansea," he said.
"It is a credit that a major company is bucking a national trend in which many companies are locating their communications abroad."
The announcement came on the same day research predicted a third of all call centres in the UK would close in the next two-and-a-half years, with the loss of 90,000 jobs.
Managing director of Mitial Research, Mike Allen, said the lower end of the call centre market would move offshore.
"We see that four in 10 basic call centres will close," he said.
"If you're at the bottom end of the call centre business in Wales your days are numbered."
The WDA accepted there was a declining UK market.
But Mike King, WDA director of South West Wales, said it was important Wales was in a strong position to fight for future investment.
"There are some small call centres and very large call centres and we want to be in the market to cover that whole spectrum," he said.
" We believe the total market is big enough to accommodate the Cleddau Bridge site and probably even more," he added.