More than a hundred properties in Galway have been investigated as suspected illegal short-term lets in the past three years.
Since the start of 2023, the City Council has investigated 98 properties, while the County Council has investigated four.
Owners, who rent out their property for short-term or holiday letting for more than 90 days a year, must secure planning permission to do so.
The Irish Independent reports the majority of the Galway City Council investigations - and all four for the County Council - have taken place this year.
Nationally, of the 1,617 investigations, Dublin City Council had the highest number at 607, followed by Cork City at 202.
No response was received by the paper from Mayo and Roscommon County Councils.
The report found the only enforcement action taken in the majority of cases was sending a warning letter to owners.
