What is a throw-in used for in soccer?

A throw-in is a method used to restart play when the ball goes out of play over the sideline. This typically occurs when the ball has been fully crossed over the touch line, whether by the player or another means, such as a defender accidentally knocking it out. The throw-in is taken by the team that did not cause the ball to go out of play, and both feet must remain on the ground, with the thrower using both hands to deliver the ball from behind their head.

The throw-in is distinct from other forms of restart, as it specifically addresses situations where the ball leaves the field at the sides, not at the goal lines, where other restarts, such as goal kicks or corner kicks, come into play. Hence, this clarifies the unique role of throw-ins in managing the flow of the game when the ball exits the field on the sides.