Setanta is hoping to launch the mobile offering by the end of the year, according to reports, with the company planning to offer a service package, including TV, phone and mobile broadband in the country.
Ireland is becoming a hub for MVNO development, and 3 has also held talks with Carphone Warehouse to launch TalkMobile.
Cable operator UPC has also signed a deal with 3 to launch an MVNO in 2015.
As part of a range of concessions, 3 is required to reserve 30% of its network capacity for the launch of two MVNOs, after its acquisition of O2 for €850 million.
The deal reduced the number of players in the Irish market to three from four, and regulators added a condition that could enable one of the MVNOs to become a full operator by acquiring spectrum in the future.
MVNOs will also be able to acquire a fixed amount of bandwidth from 3.
The European Commission, which approved 3's acquisition said "the two MVNOs that enter in Ireland in the short term will be able to replace the competitive force that 3 exercised previously".
