There are two sources of
charts.
One is a
commercial Garmin product
sold as part of their U.K. &
Ireland set
The other is produced by a voluntary group within the IWAI ( inland waterways association of Ireland ) this is very high definition based on recent sonar surveys. Great for the big lakes. But I think it’s only available in Memory-Mapper format. You have to join the IWAI to access these but they are then free. See
www.iwai.ie for details.
Alternatively there are paper charts produced for the
charter boats they are basically tourist guides and useless for real gunk holing.