Hannigan played rugby union, for the Nelson-Marlborough combined side against the 1908 Anglo-Wesh touring side. Following his rugby league career Hannigan moved back to rugby. He was a member of the Pikomanu club in the 1920s before transferring back to his old Rival club in 1926. He was still playing in 1930 for Rival and in a match against the Nelson club a spectator remarked "What! is that Pat Hannigan? I played with him 22 years ago".