ISA Softball Rules

The Independent Softball Association (ISA) releases a rule book every year to govern all of its amateur leagues in the country, encompassing 18,000 teams. It is one of the governing bodies among four major amateur softball associations around the country. Softball rules are similar to baseball rules, yet have a few minor variations.

  1. Fastpitch

    • Fastpitch softball rules are the most similar to baseball rules. There is still a strike zone and players are allowed to steal bases. The primary difference in fastpitch is that the pitcher must pitch underhand, as opposed to pitching overhand in baseball. Runners may also not take leads off the base until the pitch is released by the pitcher. Players are allowed to be substituted once in the game and re-enter the game once, unlike baseball, where once you leave the game, you can't play anymore.

    Bats

    • Bats are very strictly monitored by the ISA. They must be made of certain materials that have been approved by the ISA -- wood, carbon, graphite, aluminum, magnesium and a few others. Any composites of those materials must be approved by the ISA before they can be used in a game. The barrels can't have cracks, dents or augmentations and they cannot be more than 34 inches long or 38 ounces in weight. Anyone breaking these rules will be ejected from the game and face a possible suspension from their ISA league.

    Slowpitch

    • Slowpitch varies greatly from fastpitch softball since it is primarily a hitter's game. Slowpitch requires pitchers to pitch the ball underhand to batters at a lofting 50 to 60-degree angle. There is no stealing or leading off bases. The strike zone is marked by home plate itself and an area twice as long behind the plate marked with a rubber plate. Batters also start with one ball and one strike and may only have two foul balls.