Do you need insurance or a licene to canoe Irish rivers..?
You don’t in the UK, so I’d be very surprised if you do in Ireland. You only need licenses for powered boats as far as I know. Insurance might be useful if you’re going to canoe in the sea (SAR operations are very expensive), but you can’t really get lost on a river. If you want to canoe on waterways that pass through private property, then you’d probably need to get permission from the owner, but that’s about it. You could also try the websites below. I know they’re for the British and Northern Irish canoe clubs, but the laws are likely to be similar. Neither website seemed to have any links to a RoI site, so I don’t know if there’s an Irish national canoe club, but Google might help you there.