The Defence Forces conducted almost 200 operations in support of An Garda Síochána this year, including bomb disposals and escort duties.
In addition, it made available more than 1,200 personnel, including engineer specialist search teams to assist in various Garda search operations.
On international tasks, nearly 1,700 personnel served on United Nations' missions in 14 countries, with 650 currently on tour.
It was another year of State ceremonial duties, participating in more than 50 significant events in 2018, including the centenary of World War I and the inauguration of President Michael D Higgins.
In a statement of operations for 2018, citing provisional statistics, the Defence Forces said there was 197 'aid to civil power' operations in support of An Garda Síochána.
This includes Explosive Ordnance Disposal (bomb squad) call outs, prisoner escorts, explosive escorts, major cash escorts and search operations.
It said members continue to provide a permanent armed guard at the country's only high-security prison, at Portlaoise, as well as the Central Bank and Irish Industrial Explosives Limited.
Defence Forces' experts also supported the National Cyber Security Centre, attached to the Department of Communications.
The statement said 1,222 personnel, including members of Engineer specialist search teams, were deployed to assist Garda search operations.
It said 2,861 personnel assisted civil authorities during various operations, including combating gorse fires in Dublin, Wicklow, Limerick, Tipperary, Wexford, Down and Armagh.
Members also transported medication, staff and volunteers to deliver meals and evacuate people from cars and homes and assist in snow clearance throughout storm Emma.
The Defence Forces deployed 3,364 personnel in support of State visits and the Papal visit last August.
The Air Corps conducted in excess of 160 maritime surveillance patrol flights in 2018. It said notable operations included a multinational counter-narcotics surveillance operation.
This related to a surveillance operation on a catamaran, named Nomad, across 200 miles of waters before British border units brought it into harbour in Cornwall and seized over one tonne of cocaine.
The Navy conducted 740 boarding operations and detained seven vessels for alleged fishing infringements. Its diving section was deployed in 21 operations, including five search operations for the Gardaí.
Internationally, some 1,692 personnel served on UN peace support and security operations in 14 countries and one sea, the largest in South Lebanon with 462 personnel serving in UNIFIL.