Flag football penalties and referee signals

Updated October 25, 2026 · ~7 min read · Written by Jeddore McDonald, founder of ReadyRef

Referee signals at a glance

These are the 21 official IFAF referee signals, each with the number used in the rulebook (S5, S33...). You’ll give touchdown (S5), first down (S8) and incomplete pass (S10) on almost every drive, plus the penalty signals described below. NFL FLAG and some local leagues use different signals for a few fouls, so confirm yours in your league’s rulebook.

Common flag football penalties

Flag guarding

The ball-carrier uses a hand, arm, elbow, shoulder, or ball to block access to the flags. The IFAF signal (S52): raise an open hand, then sweep it down to the hip. Explain: "Flag guarding, offense."

Illegal contact or blocking

Flag football is built around space, not blocking. Call contact when a player pushes, screens, holds, or runs through an opponent to gain position. The IFAF signal (S38): raise one fist and grab that wrist with the other hand.

False start

An offensive player makes a sudden movement before the snap that simulates the start of the play. The IFAF signal (S19): roll the forearms over each other in front of the chest.

Offside or illegal rush

A defender crosses the line of scrimmage early or rushes from the wrong depth. In NFL FLAG, the rush line is 7 yards from the line of scrimmage unless the ball is handed off, pitched, or thrown backward, which makes all defenders eligible to rush. The IFAF signal (S18): hands on hips.

Pass interference

A player significantly restricts an opponent's chance to catch a thrown ball. The IFAF signal (S33): push both open hands forward. Light incidental contact is different from playing through the receiver.

Delay of game

The offense fails to snap before the play clock or ready-for-play count expires. The IFAF signal (S21): fold the arms across the chest.

Unsportsmanlike conduct

Taunting, arguing, unsafe behavior, or language that harms the game. The IFAF signal (S27): both arms straight out to the sides, palms down. Keep this call calm and direct: stop the behavior early before it becomes the whole game.

NFL FLAG penalty quick chart

This is a fast, game-day summary of the NFL FLAG penalty categories. Use it to orient yourself quickly, then tap through to the official NFL FLAG chart or rulebook above for the source version.

Two IFAF calls, explained with the signal, the yards and the down:

Video · 0:39Can you lateral? The hook and lateralLegal behind the line of scrimmage. Past it, an illegal backward pass: 5 yards and loss of down.

Video · 0:47Can you get in the rusher’s way?Shielding, blitzers and right of way: when stepping into a rusher’s path is a foul.

Calls refs need most often

• Defensive pass interference: a defender significantly hinders an eligible receiver's chance to catch the ball.
• Holding: restraining a player who does not have the ball.
• Stripping: knocking or grabbing the ball out of the ball-carrier's possession.
• Illegal flag pull: pulling a flag before the receiver has full possession.
• Roughing the passer: contact with the passer after a forward pass is thrown.
• Illegal forward pass: a forward pass thrown after the passer has crossed the line of scrimmage.
• Impeding the rusher: a moving offensive player occupies or blocks the rusher's path.
• Delay of game: the offense does not snap before the play clock expires; NFL FLAG references a 25-second snap window after the ball is spotted, with local enforcement details set by the rulebook.

How to announce a penalty

1. Stop the play and make eye contact with both teams.
2. Give the signal.
3. Name the foul and the team: "Flag guarding, offense."
4. State the enforcement: yardage, loss of down, automatic first down, or replay.
5. Reset the ball, down, and clock before the next snap.

Penalty enforcement varies

The exact yardage is not universal. NFL FLAG publishes baseline rules, but tournament, youth, 7v7, intramural, and NFHS-style leagues may change the penalty distance, whether a down is replayed, and how live-ball fouls are enforced. For a game that matters, check the local rulebook before kickoff.

Frequently asked questions

What is the most common penalty in flag football?

Flag guarding is one of the most common, especially with younger players who instinctively protect the belt while running.

Is blocking allowed in flag football?

In NFL FLAG youth rules, the game is non-contact and blocking or screening is not allowed. Some 7v7 and adult leagues allow limited contact, so check the local rules.

Do flag football referees use the same signals as tackle football?

Many signals overlap, but youth flag officials often simplify them so players and parents understand quickly. Clarity matters more than theatrical precision.