Ciao Giovanna!
It's super easy to cross the border with a rental car, just keep in mind the speed limit is indicated in miles in Northern Ireland and in kilometres in the Republic! The only thing you need to do is letting your rental company know beforehand you'll be crossing borders, for insurance reasons. You can find some more practical information on
vehicle rental on our website.
Seeing you're writing us from Italy, you might be interested to know we have an
Italian portal as well, and colleagues who are more than happy to help you in Italian, should you prefer.
Have you decided on a route yet?
Joris