Hi Lotte,
Thanks for reaching out.
I would recommend looking into the Leap Card, especially if you plan to travel on public transport more than once. The Leap Visitor Card is valid for Dublin and its surroundings, it’s a great way to see Dublin and beyond for 1,3 or 7 days. This is valid on all buses (Dublin Bus), suburban trains (DART) and trams (LUAS). You can even use it on day trips to the coast (Bray, Howth or Malahide for instance).
I would recommend checking
this thread out for more public transport information.
Cathaoir