Prince Harry and Meghan will visit Croke Park, Trinity College and Áras an Uachtaráin today.
The royals arrived in Dublin yesterday evening and Mary Robinson, Ibrahim Halawa and Brian O'Driscoll were among the guests at a garden party held for the Duke and Duchess.
Harry addressed the crowd at the British ambassadors residence where he made a joke about his dad.
"A special thank you to the Táiniste. Some of you know he showed my father around his home city of Cork just a couple of weeks ago... Very nice to know that he didn't bore you senseless."
Brian O'Driscoll said Prince Harry didn’t seem overly confident about England’s chances at the World Cup.
"We're just talking about life and a bit about Irish rugby and then I asked him was it coming home. He didn't seem as confident as the rest of the English nation but maybe that's just his humility."
Cervical cancer campaigner Vicky Phelan was among those invited to the party at the British Ambassador's residence.
She couldn't believe that Meghan knew who she was.
"She said yeah I've been following your story and I went 'oh my god!' I mean I knew other people knew about me elsewhere but you don't think the royals watch anything like this."