Telefonica has confirmed it's selling O2 Ireland to the Irish arm of mobile operator Three.
Three is buying O2 Ireland for €850m (£723), €780m of which will be paid upfront and the remaining €70m if the business hits certain milestones.
The combined mobile operator will have 37.5 percent of the Irish market, according to Three, and more than two million customers.
"The deal will provide Three with the scale and financial strength necessary to compete even more aggressively in the market," Three said in a statement.
The sale comes as Telefonica seeks to reduce its debt below €47bn this year — the sale of O2 will shave off €780m from that figure.
The acquisition precedes the launch of Three's LTE network, scheduled to go live in Dublin in August with maximum download speeds up to 100Mbps.
The deal is subject to regulatory approval.