Few rules in sport cause as much confusion — and as many pub arguments — as offside. Yet the core idea is simpler than the debates suggest: a player is judged offside based on where they are the moment the ball is played by a teammate, not where they end up a second later.
The basic condition
An attacking player is in an offside position if, at the moment the ball is passed to them, they are nearer to the opponents' goal line than both the ball and the second-last opponent (usually the last outfield defender, since the goalkeeper is normally last). Being in that position isn't an offence by itself — it only becomes offside if the player then gets involved in the play.
What counts as involved
A player in an offside position is only penalised if they do one of the following:
- Interfere with play by receiving the ball or touching it
- Interfere with an opponent by blocking their line of sight or challenging for the ball
- Gain an advantage from being in that position, such as the ball rebounding to them off a post
A forward can stand in an offside position all match without being flagged, as long as they stay out of play until they're back onside.
Common exceptions worth knowing
There's no offside offence from a goal kick, a corner kick or a throw-in — a striker can lurk on the last defender's shoulder in these situations perfectly legally. It's also worth remembering offside only applies in the opponents' half; you can never be offside in your own half of the pitch.
Strip away the jargon and offside boils down to one question: when the ball was played, was the attacker ahead of the last defender and about to gain an unfair advantage? Once you're watching for that single moment rather than where players drift afterwards, the decisions start to make a lot more sense.
