Semi-Automated Offside Technology — How FIFA’s 12-Camera AI System Tracks Every Player in Real Time

July 20, 2026 · 10 min read

For decades, offside decisions were football’s most agonising grey area — a linesman’s split-second judgement, a flag raised or held, and a stadium full of fans screaming at a replay they could see but the officials could not. Semi-automated offside technology has changed that equation entirely. Twelve cameras mounted under the stadium roof now track every player’s limbs fifty times per second, a sensor inside the ball detects the exact moment of contact, and within seconds the VAR team has a precise three-dimensional rendering of whether a striker was a shoulder ahead of the last defender. The question is no longer whether the technology works — it is how far it will go.

What SAOT Actually Is

Semi-automated offside technology, or SAOT, is an officiating support system designed to assist VAR teams in reviewing possible offside offences under Law 11 of the Laws of the Game. It is called semi-automated because the system generates tracking data and automated alerts, but the final decision still belongs to match officials. The referee’s whistle remains human — the technology simply gives the human better tools to blow it correctly.

The system was developed by FIFA in partnership with technology suppliers to address two persistent problems with manual VAR offside reviews: speed and consistency. Before SAOT, VAR teams used broadcast-style camera angles and manually selected frames and reference points to draw virtual offside lines. The process could take over a minute, and different operators could draw slightly different lines from the same footage. SAOT automates the heavy lifting — tracking player positions, identifying the kick point, and generating the offside line — while leaving the confirmation to human officials.

The 12-Camera Tracking System

At the heart of SAOT is a network of specialised tracking cameras. FIFA’s implementation, first used at the 2022 World Cup in Qatar, deployed twelve dedicated cameras mounted under the stadium roof. These are not broadcast cameras — they are purpose-built optical tracking systems designed to capture spatial data rather than cinematic footage.

The cameras track up to twenty-nine data points on each player, fifty times per second. Those data points include limbs, feet, knees, shoulders, and other body parts that are relevant to offside decisions. The system does not need to see a player’s full body at all times — it uses the data points it can detect to calculate the position of the ones it cannot, building a skeletal model of every player on the pitch in real time.

The number and type of cameras can vary by competition and supplier. UEFA’s system at Euro 2024 used ten specialised cameras instead of twelve, but tracked the same twenty-nine body points per player. The Premier League’s implementation, introduced from Matchweek 32 of the 2024–25 season, described its system as a support tool that automates key elements of offside decision-making for VAR, including the placement of virtual offside lines.

The Connected Ball

Tracking cameras alone can tell you where every player was at any given moment, but they cannot tell you the exact instant the ball was played. That is where connected ball technology comes in.

The Adidas Al Rihla, the official match ball of the 2022 World Cup, included a motion sensor suspended inside the ball. Adidas stated that the sensor tracked every touch of the game at a rate of five hundred times per second and supplied real-time ball data to the VAR team. FIFA described connected ball technology as an aid for determining the kick point in semi-automated offside reviews — the precise frame when an attacking player released the ball toward a teammate who may have been in an offside position.

The Adidas Trionda, used for the 2026 World Cup, also incorporated an internal motion sensor for connected-ball data. Coverage of the 2026 tournament described a system pairing optical tracking with ball-sensor data to support offside and other reviews. The sensor does not replace the cameras — it supplies ball-contact data that the system combines with the player-tracking information to identify the exact moment that matters for an offside decision.

How an Offside Check Works

When a goal is scored or a major match incident occurs, the SAOT system runs an automated check. Here is what happens in the seconds between the ball hitting the net and the referee pointing to the centre circle:

1. Detection: The tracking cameras identify the positions of all attacking players at the moment the ball was played, using the connected ball sensor to pinpoint the exact kick frame.
2. Alert: If the system detects a possible offside offence, it sends an automated alert to the VAR team. If no offside is detected, play continues without interruption.
3. Review: The VAR team examines the system’s proposed offside line and relevant match footage. They can adjust the line if the system’s automated selection needs correction, but in most cases the system’s output is accurate.
4. Confirmation: The VAR confirms the decision and communicates it to the on-field referee. The whole process typically takes thirty to forty-five seconds, compared to over a minute under the old manual system.
5. Visualisation: The system generates a three-dimensional animation showing the players’ positions at the relevant moment. This animation is displayed in the stadium and on broadcast to explain the decision to fans and viewers.

The Associated Press reported that English football expected the system to reduce the average time needed to check offside decisions by thirty-one seconds during its FA Cup introduction. That may not sound like much, but for fans in the stadium watching a goal celebration get cancelled, every second of uncertainty is an eternity.

From Arab Cup to World Cup: The Rollout

SAOT did not arrive overnight. FIFA tested the system at the 2021 FIFA Arab Cup in Qatar before deploying it at the 2022 World Cup, which was the first men’s FIFA World Cup to use the technology. The Arab Cup served as a live testing ground — real matches, real pressure, real offside calls — before the system was trusted on the world’s biggest stage.

After the 2022 World Cup, adoption accelerated across global football:

• UEFA: Introduced SAOT at the 2022 UEFA Super Cup and expanded it to the Champions League group stage from the 2022–23 season. By Euro 2024, the system was standard across UEFA’s major tournaments.
• AFC: The Asian Football Confederation introduced SAOT at the 2023 AFC Asian Cup in Qatar, implementing it at all fifty-one matches. The AFC stated this made it the first confederation to apply the technology at the continental men’s national-team level.
• Premier League: English clubs voted in 2024 to introduce the technology. After delays during testing and a trial in the FA Cup fifth round, the Premier League began using SAOT from Matchweek 32 of the 2024–25 season.
• 2026 World Cup: FIFA further integrated camera tracking, ball-sensor data, and three-dimensional visualisation tools for the tournament across the United States, Mexico, and Canada.

FIFA also tested an enhanced offside detection system at the 2025 FIFA Club World Cup. Reuters reported that the system integrated artificial intelligence, multiple cameras, and sensors in the ball to accelerate offside decision-making, while complex situations still required VAR verification before decisions were confirmed.

Accuracy and Controversies

SAOT has been promoted by football’s governing bodies as a way to reduce review times and make offside-line placement more consistent. But the technology is not without its limitations and controversies.

The “Armpit Offside” Problem

One of the most common criticisms of SAOT is that it can flag offside offences for body parts that most fans — and most players — would never consider meaningful. A striker’s shoulder or knee being millimetres ahead of the last defender at the moment the ball was played is technically offside under Law 11, but it feels absurd when the margin is smaller than the width of a boot. The technology is precise enough to detect these margins, which raises the question of whether the law should be adjusted to match the technology’s capabilities, or whether the technology should be calibrated to ignore margins below a certain threshold.

Crowded Penalty Areas

The system’s accuracy can decrease in crowded goalmouth situations where multiple players are overlapping. When ten or more bodies are packed into the penalty area during a set piece, the tracking cameras may struggle to distinguish individual limbs. The Premier League’s FA Cup trial specifically identified crowded penalty-area situations as a remaining difficulty for the technology.

Kick Point Identification

Identifying the exact moment the ball is played is critical to an offside decision, and it remains one of the system’s trickiest challenges. The connected ball sensor helps enormously, but there are edge cases — a glancing header, a deflection off a defender, a ball that brushes two players simultaneously — where the kick point is ambiguous. Updated FIFA systems have attempted to address these issues through improved camera tracking and connected-ball data, but the problem has not been fully eliminated.

Communication Delays

Even when the system reaches a decision quickly, communicating that decision to the stadium can take additional time. The three-dimensional animation that explains the offside call must be generated, reviewed, and displayed. In the Premier League’s early implementation, there were reports of fans in the stadium being confused about why goals were disallowed because the visualisation was not shown quickly enough.

SAOT vs VAR vs Goal-Line Technology

It is worth understanding where SAOT sits in the broader ecosystem of football officiating technology. The three systems serve different purposes:

• Goal-Line Technology (GLT): Uses high-speed cameras or magnetic fields to determine whether the ball has fully crossed the goal line. It is a binary yes/no system with no human review required. GLT has been in use since the 2014 World Cup.
• Video Assistant Referee (VAR): A team of officials who review match incidents using video footage. VAR covers four categories of decision: goals, penalties, direct red cards, and mistaken identity. VAR is a human system that uses video as a tool.
• Semi-Automated Offside Technology (SAOT): A tracking system that automates the detection and measurement of offside positions. SAOT assists the VAR team but does not replace them. It is specifically focused on offside decisions, unlike VAR which covers multiple decision types.

The key distinction is that SAOT is a precision measurement tool embedded within the VAR review process. It does not make decisions — it generates data that helps officials make better decisions faster. The human element remains central: the VAR team reviews the system’s output, confirms the offside line, and communicates the decision to the referee.

The Future of Offside Technology

The trajectory of SAOT development points toward faster, more accurate, and potentially more autonomous systems. FIFA’s enhanced system tested at the 2025 Club World Cup integrated artificial intelligence to handle more complex scenarios. As the technology matures, the balance between automation and human judgement will continue to shift.

Some football administrators have floated the idea of fully automated offside decisions — removing the human review step entirely for clear-cut cases. Others argue that the semi-automated approach is the right balance: the technology handles the measurement, and the human handles the judgement. The offside law itself contains subjective elements (interfering with play, gaining an advantage) that require human interpretation, even if the positional measurement is objective.

What is clear is that there is no going back. Once a competition adopts SAOT, the expectation of accuracy and speed becomes permanent. Fans, players, and managers now know that the technology exists, and they will not accept a return to the days of a linesman guessing whether a striker was level with the last defender. The genie is out of the bottle — and it tracks twenty-nine body points fifty times a second.

Key Takeaways

• SAOT uses twelve tracking cameras mounted under the stadium roof, capturing twenty-nine data points on each player fifty times per second to build a real-time skeletal model of every footballer on the pitch.
• Connected ball technology adds kick-point precision. A motion sensor inside the Adidas Trionda detects ball contact at five hundred readings per second, allowing the system to identify the exact frame when the ball was played.
• The system reduces review time by approximately thirty-one seconds compared to manual VAR offside checks, while maintaining human oversight for the final decision.
• SAOT has been adopted across major competitions including the FIFA World Cup, UEFA Champions League, Euro 2024, the AFC Asian Cup, and the English Premier League, with further AI enhancements tested at the 2025 Club World Cup.
• Limitations remain in crowded penalty areas and for marginal “armpit offside” calls, where the technology’s precision exceeds what most fans consider meaningful. The debate over the offside law itself — not just the technology — is far from settled.