Irish O2 customers talked for an average of 209 minutes a month on the network to the end of March, up from 197 minutes a month the previous year.
The number of text messages sent during 2004/2005 increased by 13% to 1.4 billion.
In comparison, O2 UK customers spend 137 minutes per month on their mobiles while O2 Germany customers spend 118 minutes.
O2 Ireland chief Danuta Gray said the profits of its Irish operation were boosted by customers talking and texting more.
“02 Ireland delivered a strong performance for the year, driven by a combination of exceptional customer growth and increased levels of usage across both voice and data services.
“We are very pleased with our performance and intend to build on this success going forward,” she added.
Turnover for the year amounted to €859m, up 13% from €762m last year.