How nice that you are considering a trip to the Emerald Isle!
According to the Citizens Information website
, UK and Irish citizens have to show photo identification when they travel by plane or ferry between the two countries. The rule of thumb is that you should carry a photo ID that follows the airline's requirements. Aer Lingus
accepts a driving license while Ryanair
seems to only allow passports and national ID's.
I'd suggest you check with your airline to make sure you have the correct travel documents.
Do you already have any travel plans while in Ireland?