Who referees the games?

This depends on the format under the Irish FA Youth Football Framework:

• 3v3, 5v5 and 7v7 (Under 6 to Under 11): there's no referee. Game supervisors call all fouls, and play restarts with a self-start (dribble or pass). Opponents stand at least 3 yards away in 3v3 and 5v5, and 5 yards in 7v7.
• 9v9 and 11v11: an official referee runs the game under the full Laws of the Game, and offside applies. If no referee turns up, the two head coaches toss a coin to decide who referees.