Gardaí inspected 15 suspected brothels across Cork and Limerick as part of an international operation targeting human trafficking and sexual exploitation.
The inspections formed part of Operation Global Chain, a Europol-led initiative carried out in June involving law enforcement agencies from 59 countries.
Gardaí say the operation has already generated new lines of inquiry and could help identify victims of human trafficking and dismantle criminal networks operating in Ireland.
Across the country, Gardaí searched 166 suspected brothels and engaged with 269 sex workers as part of welfare checks aimed at identifying people who may have been trafficked or exploited.
Detective Superintendent Derek Maguire of the Garda National Protective Services Bureau said the priority was to identify and support potential victims rather than immediately pursue enforcement action.
He said people who have been trafficked often do not disclose their situation during an initial welfare check, but some contact Gardaí days or weeks later seeking help after being given information about support services.
The operation also led to the arrest in Cork of a man in his 50s who was wanted by German authorities on allegations including child kidnapping, illegal restraint and hostage-taking. He has since been extradited to Germany.
Gardaí say intelligence gathered during Operation Global Chain will support ongoing investigations into human trafficking networks and help disrupt organised criminal groups involved in exploiting vulnerable people.