Although he played at scrum-half he was also selected for Wales at centre and fly-half.
Delahay was first capped for Wales on the 21 January 1922 in a match against England.
Delahay would be selected for all four games in the 1922 Five Nations Championship, which Wales won, but the next year, again selected for all four games in the competition Delahay was part of the Wales team that came last.
In 1923, after his switch to Cardiff, Delahay gave some terrible performances in Welsh trials,[4] and was not selected for the 1924 tournament.
After his good game for Cardiff against the All Blacks, he was re-selected to play for Wales against the same touring New Zealanders.