Earnings at communications firm Eir increased by 4pc to €441m in the nine months to March 31.
Operating costs reduced by 8pc to €287m, according to a trading update.
However, revenue at the country's largest telecoms firm fell by 2pc to €924m.
Eir said the performance was "in line with expectations".
Looking at the third quarter, turnover declined by 1pc or €3m year on year, while earnings increased by 5pc or €7m.
The company saw consistent "solid growth" in its key performance indicators, with strong year-on-year increases in fibre broadband and bill-pay mobile customers.
Eir also reported quarter- on-quarter growth in television customers, and continued growth in product bundles.
The firm had capital expenditure of €70m over the three months, which was driven by the company's continuing investment in fibre broadband as well as 4G and 5G mobile networks.
"We will continue our dedicated and determined work to ensure our network keeps Ireland connected, and we will continue to support our customers as we all adapt to new challenges and experience change," said Eir chief executive Carolan Lennon.
"Our investment programme will continue in the coming months, where it is safe to do so, with plans to roll out 5G to every major town in Ireland and continue passing more homes and businesses with superfast fibre-to-the-home broadband."
Eir had cash of €217m in March, an increase of €113m from the previous quarter.
The company said its liquidity has been further strengthened by drawing down its €50m credit facility.
In addition, it has reduced its average cost of debt by 17pc in the past year and has an average debt maturity profile of around six years.
More than 97pc of Eir's staff have been working remotely or in the field due to Covid-19, Eir has closed all but one of its Dublin offices.