Tuhia he haere tonu mo tenei whitianga - I whakaingoatia ia ki te kapa whakangungu o Ireland mo te 2013 Six Nations Championship
I te 17 o Hanuere 2013, ka puta mai i te paepae ki a Wales me Ingarangi. Na te wharanga o Mike McCarthy i whakatairanga a O'Callaghan ki te tiimata i te XV mo te keemu a Ireland ki a Scotland i te 24 o Pepuere 2013. Ko te hokinga mai o McCarthy mai i te wharanga i whakahekehia a O'Callaghan ki tetahi atu whakaaturanga i te papa i te 13<unk>13 toenga me France. Katahi ka paahitia a O'Callaghan mai i te taha o te ao, me te Devin Toner o Leinster i manakohia mo te waahi i runga i te papa ki a Itari.