touchlines

Touchlines are the boundary lines along the longer sides of a rectangular playing field. They define the lateral limits of the playing area and are considered part of the field of play. Touchlines are typically marked with white lines and extend from one goal line to the other, separating the field from the area outside the match.

In association football (soccer), the ball is out of play when it wholly crosses a touchline. Restarting play is done by a throw-in taken by the opposing team from the point where the ball crossed the line. The throw is delivered from behind and over the head with both hands, and all players must remain outside the throwing area until the ball is released.

In rugby union and many other sports, the touchline serves a similar boundary function. If the ball or a player with the ball crosses the touchline, play is halted and a restart is awarded. In rugby, this commonly results in a line-out at the spot where the ball went into touch, with teams competing to regain possession.

Beyond enforcement, touchlines help referees judge in-bounds versus out-of-bounds play, determine restart locations, and influence tactics around the sidelines. The exact dimensions and treatment of the touchlines can vary by sport, competition, and level of play, but they consistently mark the perimeter of the playable area.