When is a player in an offside position actually penalised?

Being in an offside position is not an offence. A player in an offside position at the moment the ball is played or touched by a team-mate is only penalised on becoming involved in active play by:

• interfering with play: playing or touching a ball passed or touched by a team-mate
• interfering with an opponent: by clearly obstructing the opponent's line of vision, challenging the opponent for the ball, clearly attempting to play a close ball when this impacts an opponent, or making an obvious action that clearly impacts the opponent's ability to play the ball
• gaining an advantage: by playing the ball or interfering with an opponent when it has rebounded or been deflected off the goalpost, crossbar, match official or an opponent, or been deliberately saved by an opponent

The first point of contact of the team-mate's play or touch is used (except when the goalkeeper throws the ball, when the last point of contact is used). If a player in an offside position moves into the way of an opponent and impedes their progress (for example blocks them), the offence is penalised under Law 12 instead. An offside offence is punished with an indirect free kick where the offence occurred.

Source: IFAB Laws of the Game 2026/27, Law 11 (Offside): https://www.theifab.com/laws/latest/offside/