The first-of-class LÈ Samuel Becket had been completed and delivered to Irish authorities last month in Britain and was commissioned on Saturday during a ceremony in Dublin, Ireland.
"We are delighted and proud to have successfully built, trialed and delivered this first of class OPV to the Irish Naval Service," said Babcock Shipbuilding Director Andrew Hamilton. "The success of this project has been brought about by the close co-operation of our customer, suppliers and industry.
"LÈ Samuel Beckett demonstrates that a commercial build coupled with commercial off the shelf equipment can give a high level of capability within the budgeted cost."
LÈ Samuel Becket will be used for tasks such as fishery protection, search and rescue, anti-pollution and maritime security duties.
The vessel is about 295 feet long, has a maximum speed of 23 knots and a range of 6,000 nautical miles. Among its features are a diesel electric drive system, a comprehensive command, control and communications package, a 76mm gun, two 20mm cannons and four machine guns.
Babcock International is under contract to build one more offshore patrol vessel for Ireland.