You may spot St. Flannans Cathedral across town before you actually find this amazing place of worship. Look around inside if the doors are open or just admire the facade from the street.
When you've spent a bit of time at this Killaloe principal church, why not check out Killaloe Heritage Centre, Killaloe Cathedral, and St Moluas Church? They're not very far from St. Flannan's Cathedral and also popular with many tourists.