A flag football game lasts 55 minutes, divided into two 25-minute halves with a five-minute break. Flag football teams must have seven players on the field at a time; if they have fewer than five, they forfeit automatically. Every player's flags must be visible and on top of any outerwear, and player contact is only allowed when attempts are being made to de-flag another player.
Flag football is similar to American football, but tackling is substituted with removing another player's flags.
Flag football dates back to the mid-1800s, although the exact date of the first game remains unknown. It was adopted by the American military as a recreational sport during the 1940s, and leagues began forming in the 1940s and 1950s, although the game never attracted a dominant sanctioning organization to standardize the rules. Because of this, variations have been introduced and developed, chiefly revolving around the size of the teams and whether or not linemen are allowed to catch passes. Many leagues enforce their own set of rules.
There are several international, North American, European and Asian leagues. The NFL also leads a flag football competition for young teens, attracting teams from 10 nations. Flag football is played by all age levels, including college-age students and older adults.