Here the chords that I use (Key of Eb). The Clancy brothers play this song in F.
Capo Fret 3
G G G7 G7
C G
Ar fol lol lol o horo, ar fol lol lol ay
G7 C G7
Ar fol lol lol o horo, ar fol lol lol ay
C F G7
Ar fol lol lol o horo, ar fol lol lol ay
C G G7
Fol lee fol o horo, ar fol lol lol ay