What Is Offside in Football

A player is offside only when they are in an offside position the moment a teammate plays the ball and they then become involved in active play. Standing beyond the second-last defender is not a foul in itself. Law 11 requires three distinct elements before an assistant referee raises the flag: position, timing, and involvement. Remove any one and play continues.

This distinction between the position and the offence is the core of the rule. A player caught in an offside position who does not interfere with play, does not challenge an opponent, and does not gain an advantage from a rebound has committed no offence. IFAB has refined the definitions of involvement repeatedly, most recently clarifying which actions constitute interfering with an opponent, but the three-part test has been stable for two decades.

An offside position is a static condition. A player is in an offside position if any part of the head, body or feet is nearer to the opponents' goal line than both the ball and the second-last opponent, and if they are in the opponents' half. The hands and arms of all players, including the goalkeeper, are not considered. A player level with the second-last opponent is not in an offside position.

An offside offence is a dynamic action. It occurs only when a player in that position becomes involved in active play at the moment a teammate touches or plays the ball. The moment of the pass is the critical frame. If the player is onside when the ball is kicked and runs beyond the defender a split second later, no offence has occurred. The reverse is also true: a player who was offside when the pass was made but does not touch the ball, block an opponent, or chase a rebound has not committed an offence.

The timing element causes more errors at amateur level than any other part of Law 11. A striker who stands five metres offside while a teammate dribbles, then receives a pass only after dropping back onside, has committed no offence because position is judged at each pass, not across a phase of play. This is not a loophole. It is the rule functioning as designed.

Interfering With Play

Interfering with play means playing or touching a ball passed or touched by a teammate. The contact must be deliberate. A ball that brushes a stationary offside player's heel without that player making a conscious movement is not an offence, though IFAB's current interpretation means any contact in an offside position that changes the ball's path is likely to be penalised. The safest assumption: if the ball touches you while you are offside and it came from a teammate, the flag is going up.

Interfering With An Opponent

This covers four specific actions: preventing an opponent from playing or being able to play the ball by clearly obstructing their line of vision, challenging an opponent for the ball, clearly attempting to play a ball that is close when the action impacts an opponent, or making an obvious action that clearly impacts the opponent's ability to play the ball. The word 'clearly' does heavy lifting here. A striker who stands still while a defender heads clear has not interfered. One who jumps at the ball and forces the defender to adjust has. This is the most subjective of the three involvement forms and the most common source of disputes at VAR reviews.

Gaining An Advantage

Gaining an advantage means playing the ball after it has rebounded or been deflected off the goalpost, crossbar, match official, or an opponent, or after a deliberate save by any opponent. The deliberate save clause is specific: if a goalkeeper parries a shot, the ball is still live for other attackers, but an offside player cannot touch the rebound. If the goalkeeper makes a controlled catch and then drops the ball, that is a new phase of play and the offside position resets. A deflection that does not involve a deliberate save does not create a new phase, so an offside player who collects a deflected pass remains offside.

Call each scenario before reading the explanation. If you get them right, you understand Law 11.

A forward stands five metres offside when a teammate shoots from 20 metres. The goalkeeper dives and parries the ball. The forward collects the rebound and scores. Decision: offside offence, gaining an advantage from a deliberate save. Score disallowed. The forward was offside at the moment of the shot and the goalkeeper's parry is a save, not a new phase.

A midfielder chips a pass over the defence. An attacker starts their run from an onside position, level with the second-last defender, and sprints onto the ball. The assistant's flag stays down. Decision: correct. Position is judged at the moment the ball is played, not when it is received. The attacker was onside when the pass was struck.

A corner is taken short. The receiver passes back to the taker, who is now beyond the second-last opponent. Decision: offside offence. The taker was in an offside position when the return pass was made. The corner kick exception applies only to the first touch directly from the corner.

A player receives the ball directly from a throw-in while standing behind every defender. Decision: no offence. There is no offside offence if a player receives the ball directly from a goal kick, a corner kick, or a throw-in. These three restarts create a specific exemption in Law 11.

The Three Absolute Exceptions

Law 11 contains three absolute exceptions. A player cannot be offside from a goal kick. A player cannot be offside from a corner kick. A player cannot be offside from a throw-in. The ball must come directly from the restart. If a goal kick is headed on by a teammate and an offside player collects it, the offence is called. The exemption applies only to the first touch.

The Halfway Line Boundary

The halfway line acts as a hard boundary. A player cannot be in an offside position if they are in their own half of the field at the moment the ball is played. Even if every outfield opponent is in the attacker's half, an attacker standing on the centre circle line in their own half is onside regardless of where the defenders are. This rule is absolute and causes no interpretive disputes.

Who Counts As The Second-Last Opponent

The second-last opponent is almost always the last outfield defender, with the goalkeeper counting as the last opponent. If the goalkeeper is ahead of a defender, the roles swap. In the rare case of two defenders on the goal line and the goalkeeper upfield, the second-last opponent is one of those defenders. The law does not require a goalkeeper to be the last opponent, only that two opponents exist between the attacker and the goal line.

Delayed Flagging Protocol

The assistant referee is instructed by IFAB to keep the flag down in any situation where the involvement is unclear until the phase of play concludes. Delayed flagging is the standard protocol in professional football, meaning a clear offside may not be signalled for several seconds while the referee and assistant determine whether the offside player actually becomes involved. This policy reduces the number of incorrect early flags that kill promising attacks where the offside player was irrelevant.

Amateur Versus Professional Application

At amateur and grassrots level, where there is no VAR and often only one match official, the flag is raised immediately because the delayed protocol requires a second official to assess involvement. This divergence between the televised professional game and the park pitch is the single biggest source of confusion among new viewers. The law is the same. The application differs because the officiating resources differ.

When Inaction Keeps You Onside

A player who moves into an offside position but makes no attempt to play the ball, does not block any opponent, and does not move toward a rebound has committed no offence even if they stood in an offside position for ten seconds while play continued around them. The moment they step toward the ball or an opponent alters their movement because of them, the offence is committed.