The State's largest mobile phone operator Vodafone has signed deals with ESB Telecoms and E-net, the firms managing the State's telecoms networks.
Vodafone has agreed to invest €10 million in the contracts with the two companies to give it access to the telecoms networks they manage across the Republic.
The 10-year agreement will enable Vodafone to expand the voice and data traffic that it offers its 1.9 million subscribers.
The deal was agreed between Vodafone, E-net and ESB Telecoms following a national tender competition involving a number of Irish-based telecoms firms.
The contract award is one of the biggest deals that E-net, the company managing the State's regional broadband network, has won since it started operating.
E-net currently manages 20 fibre optic telecoms networks recently built by the Government around towns and cities in regional areas.
It is due to take on management of scores of other regional networks planned under a €170 million Government strategy to boost infrastructure.
Tom Savage, chief operations officer of E-net, said its fibre optic networks would provide Vodafone with the capacity to offer advanced high-bandwidth services to its customers.
This extra capacity is necessary for Vodafone, which is currently rolling out its third generation (3G) mobile phone service across the State.
The new 3G system enables subscribers to send video clips and photographs to each other. It also enables them to download music and video games onto their handsets.
Sheila Kavanagh, head of Vodafone's transport networks division, said the deal would help the firm to grow and expand.
"These agreements form part of our long-term strategic plans to ensure that we continue as Ireland's leading operator," she said.
The deal with Vodafone will also provide a boost for ESB Telecoms, which operates a national backbone telecoms network that links a number of key towns and cities across the Republic.
ESB Telecom's fibre optic network is reserved for use by other telecoms operators that need to provide services outside Dublin.