The telecoms regulator has awarded the country's fourth 3G licence to Smart Telecom.
Smart Telecom won over bids from fixed line operator Eircom and mobile phone operator, Meteor, which Eircom is in the process of buying.
"Smart's application earned high points in particular on speed of network rollout and coverage to be provided at key milestones, backed up by attractive performance guarantees," the Commission for Communications Regulation said in a statement.
"As a new market entrant to the Irish mobile market they earned maximum points under the promotion of competition criterion. As a result of these markings relative to the other applicants they emerged as the first-ranked applicant and are therefore being offered the licence."
The three previous 3G licences were awarded to 3 Ireland; owned by Hong Kong-based Hutchison Whampoa with Britain's O2 and Vodafone gaining licences following a tender in 2002.
The licence on offer is a so-called 'B' licence to provide third-generation mobile services - which allow for higher speed transmission of information and Internet access - for a period of 20 years.
The 3G 'B' licence provides for a minimum of 53 per cent coverage to be achieved by October 2011, equivalent to coverage of the five major cities.