The Offside Trap



The “offside trap” in soccer is a defensive maneuver where, just before the attacking opponent is about to pass the ball to a leading striker, all of the defensive backs move upfield in unison, placing the leading striker behind them in an offside position.  Assuming the striker receives the ball, thereby gaining an advantage from having been in the offside position, the striker is caught or “trapped” in violation of Law 11 of the Laws of the Game, “Offside.” As a result, the violation is expected to be called by the officials and an indirect free kick awarded to the defending team.  In order to understand the context of how the Law is applied to the offside trap (“the trap”) see, in order, “Introduction to Offside,” “Offside – The Basic Scenario,” and “Offside – The More Complicated Portions.”


First introduced in the 1900s, many teams around mid-century adopted the offside trap as an integral part of their defensive strategy.  This proved useful when the offside law was interpreted in a less problematic way and almost any striker placed in an offside position by the trap, whether gaining-an-advantage/interfering-with-play or not, had a chance of being called for “offside.”  Whereas the defense always assumed the risk that the trap might be beaten, recent changes to the offside law and to team offensive tactics have caused the trap to become even riskier for the defending team.  On the one hand, where once a simple through ball toward a player in an offside position may have drawn the call, now attackers “not involved in active play,” although in an offside position, are less likely to be deemed in violation.  On the other hand, it is currently much more common for teams to use crisp, short, inter-passing on attack, rather than a lot of through balls, which also has the effect of reducing offside calls.

offside trap
The Offside Trap – Defenders (in red) move up in unison.


Using the offside trap poses a calculated risk for the defense.  Since the Law requires that an attacker have at least one defender between him and the goal (usually the goalkeeper) and also be level with the next-to-last defender at the time the ball is played in order to be in an onside position, all of the defensive backs stepping forward in unison leaves the goalkeeper alone. If the trap is effective, the defenders have succeeded in winning the ball without having to make a challenge or a tackle.  If the trap is unsuccessful, the goalkeeper suffers the consequences.  The most common cause for the offside trap to fail is that one of the back defenders does not move upfield at the exact same time as his teammates, thereby leaving the attacker(s) in an onside position just as the other defenders vacate the space.  Another is that an attacker, upon recognizing that he is about to be “caught,” may simply choose to essentially stand still, thereby avoiding interfering with play, and let a teammate who had been onside move to play the ball.

Tactical/Coaching Decisions

Before introducing the offside trap, coaches must determine if its use is appropriate for their team.  First, because of the on-field decision-making, timing, and coordination involved, players need to be mature enough and sophisticated enough to understand the Offside Law and the concepts associated with the trap.  Second, coaches need to consciously determine if the benefits involved in using the trap outweigh the risks. Not only can a small error result in a goal, but the team has to have a mentally strong goalkeeper who is willing to accept whatever happens.

The offside trap may be appropriate to be used against some opponents but not for others.  Teams that play a lot of through balls are likely to be more vulnerable to the trap.  These teams also tend to clearly show when they are going to attempt those through balls, in addition to chips and other long balls.  If they are not prepared for it, constantly having their attacks killed by the trap can be incredibly demoralizing.  Opponents who play a lot of short, quick passes on attack are far less vulnerable to the trap, however, especially if they have fast strikers with exceptional ball skills.  These teams also tend to be better at recognizing and defeating the trap.

Whether or not to use the trap may further be based on the formation and system of play being utilized.  Recognizing that all of the back defenders must step up in unison to implement the trap, a team that uses a flat-back-four alignment is more conducive to proper execution.  In comparison, a team using a stopper-sweeper alignment often keeps attackers in onside positions because of the location of the sweeper behind the other back defenders.  Under any condition, effective performance of the trap comes with practice, repetition, experience and familiarity among players over time.

The use of the offside trap can be applied to two different circumstances:

  • Normal run of play. 
  • Free kicks.

Coaches need to determine which of these, or both, are going to be used and the conditions that must exist for the trap to be implemented.  Further, coaches must have full confidence in the upfield defensive coordinator (a designated central defender) to recognize when the conditions apply and to properly execute the call for the trap.

Status of the Back Defenders

Just before the trap can be executed, all of the back defenders (fullbacks, back line) need to be in a straight line across the width of the field.  This may be three or four players, depending on the formation, or may include a defensive midfielder.  This establishes the imaginary “line of offside,” which must be parallel to the halfway line.  It is okay for a defender to move ahead of this line, but never behind.  It is critical that the back defenders:  a.) move up or back in unison; b.) know the position or location of each of their other back defenders at all times; c.) know where all of the opposing strikers are at all times; d.) understand when the opponents are likely to pass the ball forward; e.) know who is authorized to make the offside trap call; f.) know what the signal for the trap looks or sounds like; and g.) recognize the circumstances under which the call for the trap is most likely to be made.  Constant and effective communication among the backs is critical to making all of this work.  (See “On-field Oral Communication.”)

Two other items apply to the back defenders.  First, technically, at least one attacker must be in the defensive half of the field.  If all of the attackers are in their half of the field, there can be no offside.  Similarly, at least one attacker needs to be ahead of the ball.  Second, there needs to be enough space on the field, both in front of and behind the defenders, in order to move efficiently.

Again, the single most important key to the proper function of the offside trap by the back defenders is the ability to move as one unit.   Any single player who fails to move up, thereby leaving an attacker onside, defeats the entire trap.

Who Calls for the Trap

There can be one, and only one, defender designated to be responsible for calling the offside trap.  In a four-back alignment, this is usually one of the two center-backs, otherwise identified as the upfield defensive coordinator.  In a three-back alignment, it is usually the center fullback.  In a stopper-sweeper alignment, it can be the sweeper upon moving forward to line up with the other defenders.  (For certain free kicks, it can also be the goalkeeper, but this requires great coordination, understanding, and a separate signal.)  No player, other than the designated defender, may call for the trap.

The upfield defensive coordinator directs the defense through the normal run of play, using both oral and non-verbal communication.  (See “On-field Non-verbal Communications.”) Clearly, not making the call for the trap means the defense is to operate as normal, dropping back as appropriate to mark, cover, balance, stay goal-side, intercept, control, and tackle.  Otherwise, the designated defender judiciously picks his spots to call for the trap.   When the opportunity presents itself, just as the attacking team is about to play the ball forward, he makes the split-second decision and performs the signal for the trap.

Signal for the Trap

The actual, literal, signal for the trap may be verbal or non-verbal.  Either way, it must be unique and understood by all.  A verbal signal, something like calling out the word “red,” must be able to be heard clearly by all defenders on both sides of the field.  This can cause a problem in a stadium full of noise.  As such, a non-verbal signal, such as raising an arm overhead, tends to be preferred.  Like any signal, it is subject to being seen or heard by the opponent, especially if having been scouted, and may have to be changed between games.  Coaches may devise far more subtle signals, but they have to ensure that they can be easily recognized by all of the back defenders for the communication to be received.

Execution of the Trap (“Springing the Trap”)

All back defenders must be able to read the circumstances where the trap may be called and be prepared to react accordingly.  The trap is performed very quickly with little margin for error.  Failure to recognize the circumstances and to react to the signal at a moment’s notice can result in a player being kept onside and a goal being conceded.

Clues that a trap may be called include that the leading attackers have started their forward runs and that the player with the ball, who is behind the forward attackers, has generally just looked down to see the ball before making his pass.

When the call for the trap is made, the back defenders must step forward instantly and in unison.  “Stepping forward” is actually a three- to five-yard sprint, ensuring that there is no doubt in the mind of the Assistant Referee or the Referee that there is clear space between the next-to-last defender and the attacker when the ball is played.

See the YouTube video: Japan trap versus Senegal

Japan, in blue, pulls a wildly successful trap against a free kick.  Note how the Japan midfielders, by design, rush to fill the vacated space in case something goes wrong.


Repeat the trap in practice over and over until it becomes second nature.  Do not use it in games until everyone is comfortable.  Vary the situations.  Practice for the defense performing the trap is also an opportunity for the offense to practice how to beat the trap.

Soccer Coaching Tips:

  • See “Beating the Offside Trap.”
  • You may only be able to use the trap effectively once in a game.  For a well-coached opponent, the first time they are trapped may come as a surprise to them, but from then on, they are likely to be prepared for it.  Over-use of the trap increases the risk of the opponent figuring it out, beating it, and scoring.  This gives rise to the phrase, “Live by the trap, die by the trap.”
  • This is a team trap.  No player, other than the upfield defensive coordinator (designated center back), or possibly the goalkeeper, can make an individual decision.
  • Remember that your team may have been scouted.
  • The other team may know the signal and sometimes it may have to be changed.  (The trap happens so quickly, however, that it may not matter.)
  • The other team may be very good at beating the trap.  Opponents need to be scouted.  (Particularly if the trap is used against a free kick, coaches may designate to players, usually midfielders, to run into the space behind the trap as it is being executed, in case the trap is beaten.)
  • If a back defender can not stay focused, or if they engage in “ball watching,” then the trap may not be a good option.
  • Recognize that, upon first teaching the trap, it is hard for defenders to learn how to intentionally let the opponent go past.

© Copyright, John C. Harves