The touchlines, also referred to as sidelines, are the two long lines running the length of the field, positioned equidistant from each other. These lines define the field's boundaries, marking the area where the ball must remain in play during the match. If the ball crosses a touchline and goes out of bounds, the opposing team is awarded a throw-in. In the diagram below, the touchlines are highlighted in blue.

The touchlines, also referred to as sidelines, are usually between 70 and 130 yards long for a standard soccer game and between 110 and 120 yards long for international matches.