Eir has become the second mobile operator to launch a 5G mobile network here.
The new service will initially be available from 100 sites serving 10 towns and cities around the country, with another 100 to follow in the coming weeks.
The locations are Dublin, Cork, Limerick, Galway, Waterford, Carlow, Castlebar, Dundalk, Drogheda and Kilkenny.
100 additional sites in Athlone, Bray, Ennis, Letterkenny, Sligo, Tralee and Trim will be added before the end of year.
Eventually eir says it will roll out 5G coverage to every major town in Ireland.
The network will offer connection speeds of over 1Gbps.
The company claims it is the largest 5G network coverage of any operator here.
However, only Vodafone has so far launched a mobile 5G service. Imagine is offering high speed broadband over a fixed 5G network in certain parts of the country. Three's 5G service has not yet gone live.
"eir is transforming its mobile network and 5G will complement on-going upgrade and expansion of our 4G network, which will bring high voice and high-speed data coverage across more than 99% of the population of Ireland, allowing our customers to access high speed data services on the most expansive 4G mobile network in Ireland," said CEO Carolan Lennon.
Eir says it will also offer a number of different 5G ready handsets to customers, starting at €99.
These will include the Samsung A90 5G, the Samsung S10 5G, the Samsung Note 10+ 5G and the Huawei Mate 20X 5G.
Initially the service will be on offer through the Connect Plus plan.
This includes unlimited data (with a fair usage cap of 80GB), unlimited calls and texts, 100 international minutes and texts and access to the new eir Sport App.
It will cost existing eir broadband customers €49.99 a month and new customers €59.99.
Vodafone launched their 5G offering in August in Cork, Dublin, Galway, Limerick and Waterford.