Delahay first came to prominence as part of Bridgend Rugby Football Club, and played his first eight games for Wales while with the club. Delahay switched to first-class club Cardiff in 1923, and after leaving Cardiff, turned out as a veteran for Torquay Athletic and Devon. In 1924 Delahay was part of the Cardiff team to face the touring All Blacks, and although Cardiff lost 8–16, he scored a memorable try. Delahay captained Cardiff during the 1926/27 season.
Delahay was first capped for Wales on the 21 January 1922 in a match against England. Delahay was one of eight new caps on the day and Wales beat England easily, scoring eight tries, Delahay scoring one of them. 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.
Delahay would play all games in the 1925 and 1926 Five Nations Championships, and in the final game of the 1926 tournament he was selected as Wales captain in the game against France.
International matches played for Wales[5]
England 1922, 1923, 1925, 1926
France 1922, 1923, 1925, 1926
Ireland 1922, 1923, 1925, 1926
New Zealand 1924
Scotland 1922, 1923, 1925, 1926, 1927
