Google's Irish operations made a profit before tax last year of €1.68bn, up 26% on a year earlier.
The tech giant paid €272m in tax on that profit, an effective rate of 16%, newly filed accounts show.
Turnover for the 12 months was €38.1bn, up €5.9bn or 18% on the 2017 figure.
Google Ireland Ltd said the rise was primarily driven by an increase in advertising revenue.
At the end of the year, 3,765 people were directly employed in its operations here, up 9.8% on a year earlier.
Including salaries, social welfare costs, pensions, and share based payments, the average cost per employee was €151,922.
The average salary per employee was €104,329.
"2018 was a milestone year for Google as we celebrated 15 years in Ireland," said a Google spokesperson.
"Our Irish office continues to play a key role in our Europe, Middle East and African (EMEA) business. As well as growing our turnover, we also added over 300 new jobs in 2018."
Administrative expenses climbed €3.2bn to €25.1bn, caused by an increase in employee numbers required to support the growth of the business as well as royalty payments to the group.
Sales and marketing efforts across the EMEA region also added to costs.
Cost of sales were €2.6bn higher at €11.6 billion. This includes money paid to Google Network Members, as well as to distribution partners who make available Google's search access points and services.
As well as running its EMEA search and advertising business from here Google also has two data centres in Dublin.
Total assets rose from €7.8bn in 2017 to €9.6bn by the end of the year.
In the accounts Google identified the principle risks it faces as intense competition, the danger that manufacturers and users do not adopt its technology, the possibility of falling advertising revenue, increased regulatory scrutiny and privacy concerns.