Section 1: Introduction
Softball is played and governed internationally by the World Baseball Softball Confederation (WBSC). The sport's current playing rules are set out in the Official Rules of Softball – Fast Pitch, 2026-2029 edition, released by the WBSC in December 2025 and effective from January 1, 2026 for all international competitions of the four-year cycle, including the Los Angeles 2028 Olympic Games. These Official Rules govern the play of Fast Pitch and Modified Fast Pitch softball in any game, tournament, or competition, whether or not it is a WBSC Competition, and apply in addition to any applicable Tournament Regulations.
Softball is contested between two teams of nine (or ten, when a Designated Player is used) that alternate at bat and in the field. Rule 1.1.4 defines the home team as the team that starts the game on defense and bats in the bottom half of each inning, while the visiting team starts on offense and bats in the top half. Rule 1.1.5 defines an inning as the segment of a game in which both teams have a turn at bat and in the field, each half-inning ending after three outs.
Under Rule 1.2.1, a regulation game consists of seven completed innings, unless the home team is ahead after the visiting team's half of the seventh (in which case the bottom of the seventh is not played), or the run ahead (mercy) rule is invoked. Games tied after seven innings continue with extra innings, using the international tiebreaker procedure described in Rule 1.2.4, until a winner is determined.
Section 2: Equipment
Bat. Per Appendix 2.A, an official bat must be of one-piece, multi-piece permanently assembled, or two-piece interchangeable construction, stamped with the WBSC (or former ISF 2005) approved marking. A bat must be no more than 86.4 cm (34 in.) long and no heavier than 1,077.0 g (38 oz.), and no more than 5.7 cm (2¼ in.) in diameter at its largest part (a tolerance of 0.80 mm/&frac132; in. is permitted for expansion). Non-wooden bats must have a safety grip of cork, tape, or composition material at least 25.4 cm (10 in.) long and a safety knob of at least 0.6 cm (¼ in.) protruding at a 90-degree angle from the handle. A separate warm-up bat, marked "warm-up" in 3.2 cm letters on the barrel and with a barrel end in excess of 5.7 cm, may only be used per Appendix 2.B.
Ball. Per Appendix 3, the official softball is a smooth-seamed or flat-surfaced, concealed-stitched 30.5 cm (12 in.) ball measuring between 30.2 cm (11⅞ in.) and 30.8 cm (12⅛ in.) in circumference, weighing between 178.0 g (6¼ oz.) and 198.4 g (7 oz.), with not less than 88 stitches sewn by the two-needle method. Balls used in WBSC Competitions must carry a white or yellow optic cover with white or red stitching, a Coefficient of Restitution (COR) of .47 or under, and require no more than 170.1 kg (375 lb.) of load force to compress the ball 0.64 cm (0.25 in.), per the ASTM test methods adopted by the WBSC Equipment Standards Commission.
Gloves and mitts. Rule 2.4.1 permits any player to wear a glove, but only the catcher and first baseman may use a mitt (a glove with a solid, deeper pocket and no separated finger slots). No top lacing or webbing on a first baseman's or catcher's mitt, or a fielder's glove, may exceed 12.7 cm (5 in.) in length. A pitcher's glove may be any color, provided no part of it (including lacing) is the color of the ball; any glove or mitt with white, gray, or yellow optic circles that give the appearance of a ball is illegal (Rule 2.4.1d).
Helmets. Rule 2.1.9 requires an on-deck batter, batter, batter-runner, runner, youth coach, and bat person to wear a helmet with two ear flaps and safety features equal to or greater than those provided by full plastic cladding with padding on the inside; a helmet that is cracked, broken, dented, or altered is illegal and must be removed from the game.
Catcher's protective equipment. Rule 2.4.3 requires every catcher to wear a mask, throat protector, and helmet, including while receiving warm-up pitches from the pitcher's plate or in the warm-up area. Both adult and youth catchers must also wear a body protector and shin guards offering protection to the kneecap while on defense.
Shoes and uniforms. Rule 2.4.2 requires all team members to wear shoes with canvas or leather uppers, ordinary metal or molded cleats (spikes not extending more than 1.9 cm/¾ in.), with hard plastic, nylon, or polyurethane spikes prohibited at any level. Rule 2.5.1 requires all players on a team to wear uniforms alike in color, trim, and style, including mandatory caps for male players, and a contrasting-color Arabic number 15.2 cm (6 in.) tall on the back of every shirt, with no two players on a roster wearing the same number.
Section 3: Playing Area
Appendix 1 sets out the official diamond and field layout. Bases are 18.29 m (60 ft.) apart, measured from the back part of home plate to the back of first and third base; home plate to second base measures 25.86 m (84 ft. 10¼ in.) to the middle of the base. Home plate is a five-sided figure 43.2 cm (17 in.) wide across the edge facing the pitcher, with sides 21.6 cm (8½ in.) long parallel to the batter's box lines and a point facing the catcher formed by two 30.5 cm (12 in.) sides. The pitcher's plate is a rubber slab 61 cm (24 in.) long and 15.2 cm (6 in.) wide, with its top level with the ground.
Per the Appendix 1.F Distance Table, pitching distance and minimum outfield fence distance vary by division: Junior Women's 15-and-under pitch from 12.19 m (40 ft.) with a 60.96 m (200 ft.) minimum fence; Junior Women's 18-and-under and Women's pitch from 13.11 m (43 ft.) with a 67.06 m (220 ft.) minimum fence; and Junior Men's and Men's pitch from 14.02 m (46 ft.) with a 76.20 m (250 ft.) minimum fence.
The batter's box on each side of home plate measures 0.91 m by 2.13 m (3 ft. by 7 ft.), with its inside line 15.2 cm (6 in.) from home plate and its front line 1.22 m (4 ft.) in front of a line through the center of the plate. The catcher's box measures 3.05 m (10 ft.) long and 2.57 m (8 ft. 5 in.) wide behind home plate. A one-meter (3 ft.) running lane is drawn parallel to and one meter from the baseline between home and first base, starting halfway between the two bases. The on-deck circle is a 1.52 m (5 ft.) circle of 0.76 m (2 ft. 6 in.) radius adjacent to the dugout end closest to home plate, and the pitcher's circle is a 4.88 m (16 ft.) circle of 2.44 m (8 ft.) radius drawn from the center of the front edge of the pitcher's plate.
A double first base – a fair-territory base joined to a foul-territory base of a contrasting color – is used to separate the batter-runner's running path from the first baseman's fielding path under Rule 5.6. The backstop and sidelines (dead-ball line) must be set back a minimum of 7.62 m (25 ft.) and a maximum of 9.14 m (30 ft.) outside the foul lines, and a warning track of dirt or gravel, distinguishable from the playing surface, must run a minimum of 3.66 m (12 ft.) to a maximum of 4.57 m (15 ft.) inside the outfield and/or side fences.
Section 4: Players & Officials
Rule 3.2.2 requires every team to have a minimum of nine players in the line-up at all times, occupying the positions of pitcher (F1), catcher (F2), first baseman (F3), second baseman (F4), third baseman (F5), shortstop (F6), left fielder (F7), center fielder (F8), and right fielder (F9). If a team elects to use a Designated Player (DP) under Rule 3.1.3, it must list ten players, with the DP batting for the FLEX (Rule 3.1.6), the tenth player named in the line-up who may play any defensive position without batting.
A starting player who has been substituted for may re-enter the game once, in the same batting position, under Rule 3.1.15 (re-entry); a second re-entry, or re-entry in a different line-up position, is an illegal re-entry (Rule 3.1.7). A replacement player may enter for a player who has been withdrawn due to a bleeding injury under Rule 3.1.23, and a temporary runner may run for a catcher or the pitcher of record once that player is on base with two outs (Rule 3.1.22).
Rule 3.4.3 permits up to two base coaches, each required to remain with both feet within the confines of the coach's box while giving direction to batters and runners. A coach or manager under Rule 3.4.1 is responsible for notifying the Plate Umpire of any line-up change and may not use language or gestures that reflect negatively on players, umpires, or spectators.
Rule 3.6 establishes the umpiring crew: the Plate Umpire has full charge of and is responsible for the proper conduct of the game, decides the fitness of the field, calls all balls and strikes, and determines when a game is forfeited, while Base Umpires assist in enforcing the rules from positions on the field. Under Rule 3.6.6, an umpire's judgment on close plays – fair or foul, safe or out, ball or strike – is not reversible except when it conflicts with the rules themselves.
Section 5: Rules of Play
Pitching. Rule 4.3.3 requires the pitcher's delivery to be an underhand windmill or slingshot motion, with the hand below the hip and the wrist no farther from the body than the elbow, no stop or reversal of the forward motion, and the release and follow-through forward and past the straight line of the body. The pitcher may make only one revolution on the windmill pitch and must take one step with the non-pivot foot simultaneous with release, remaining within the 61.0 cm (24 in.) length of the pitcher's plate (Rule 4.3.3e). The pitcher has 20 seconds to release the next pitch after receiving the ball or the umpire's "Play Ball" (Rule 4.3.3k). A pitcher who pushes off from a spot other than the pitcher's plate (a "crow hop," Rule 4.1.2) or who becomes airborne with both feet before landing and continuously delivering the ball ("leaping," Rule 4.1.4) commits an illegal pitch. Each defensive team is limited to three charged defensive conferences in a seven-inning game under Rule 4.2.1; a fourth or subsequent conference in the same game results in the pitcher being declared an illegal pitcher.
Batting. Rule 5.4.3 defines the strike zone in Fast Pitch as the space over home plate between the bottom of the batter's sternum and the bottom of the batter's kneecap when the batter assumes a natural stance. A batter is out under Rule 5.4.4 after three strikes are called (unless the "dropped third strike" rule of Rule 5.1.46 applies with fewer than two outs and first base unoccupied) and is awarded first base after four called balls (Rule 5.1.1). Rule 5.5.1g defines a home run as a fair batted ball that clears the outfield fence in flight over fair territory, or contacts a fielder's glove or body and continues over the fence in fair territory.
Base running. Under Rule 5.10.1, a runner may legally attempt to steal or advance on a pitch, passed ball, or wild pitch only after the pitcher's non-pivot foot touches the ground during the pitching motion. Rule 5.1.26 defines an infield fly as a fair fly ball, other than a line drive or an attempted bunt, that an infielder can catch with ordinary effort when first and second, or first, second, and third bases, are occupied with fewer than two outs; the batter is automatically out regardless of whether the ball is caught. Rule 5.1.19 (force out) and Rule 5.9 (touching bases in order) govern appeal plays for missed bases or runners leaving too soon on a caught fly ball.
Section 6: Scoring
Rule 1.2.5a provides that one run is scored each time a runner legally touches first, second, and third base and home plate, in order, before the third out of that half-inning. Rule 1.2.7 declares the winner of a game as the team that scores more runs than its opponent in a regulation game; a game called by the Plate Umpire is a regulation game if five or more complete innings have been played, or if the team second at bat has scored more runs in five or more innings than the other team has scored in an equal or greater number of innings. A forfeited game is scored 7-0 in favor of the team not at fault (Rule 1.2.7c).
Rule 1.2.5c specifies that a run does not score if the third or last out of the inning results from a batter-runner being put out before reaching first base (including on appeal), a runner being forced out, a runner leaving a base before the pitcher's non-pivot foot touches the ground during the pitching motion, or a preceding runner being put out. The Run Ahead (mercy) Rule of Rule 1.2.3 ends a game early when one team leads by fifteen runs after three innings, ten runs after four innings, or seven runs after five completed innings.
The Tiebreaker Rule (Rule 1.2.4) applies starting in the top of the eighth inning and each half-inning thereafter: the offensive team begins its turn at bat with the player scheduled to bat ninth in that half-inning placed on second base as a runner, and that runner does not need to touch first base for a run to score if driven in.
Section 7: Violations & Penalties
An illegal pitch under Rule 4.3 (Effects, Rules 4.3.1 to 4.3.7) is ruled a delayed dead ball: a ball is awarded to the batter if the pitch is not hit, and if the batter hits the illegal pitch, the offense has the option of taking the award for the illegal pitch or the result of the play. A pitcher removed from the pitching position for repeatedly violating the pitching rules, or for exceeding the charged defensive conference limit, is declared an illegal pitcher under Rule 4.8 and may not return to pitch for the remainder of the game, though the player may play another defensive position or bat.
Batting out of order (Rule 5.4.1) is an appeal play: if discovered before the incorrect batter completes their turn at bat, the correct batter may take their place and assume the existing ball-and-strike count; if discovered after the incorrect batter has completed a turn at bat, the proper batter is declared out and any advance or score resulting from the improper at-bat is nullified.
Rule 5.1.30 (interference) and Rule 5.1.32 (obstruction) carry base-award or out penalties depending on which team commits the violation: an offensive player who impedes a fielder attempting to make a play is called out under the relevant provisions of Rule 5.10.3, while a fielder who impedes a runner without possessing the ball, and not in the act of fielding a batted ball, results in the obstructed runner and other affected runners being awarded the base(s) they would have reached absent the obstruction (Rule 5.10.2). A batter who enters the box with, or is discovered using, an altered or illegal bat is ejected from the game and the bat is removed (Rule 5.4.3.b.iii). A game may be forfeited to the non-offending team under Rule 1.2.2 for reasons including a team's refusal to continue play, failure to field the required number of eligible players, or repeated rule violations after an umpire's warning.
Section 8: Safety Considerations
The Official Rules embed several mandatory safety requirements. Rule 2.1.9 and Rule 5.4.2a require every batter, on-deck batter, batter-runner, and runner to wear a double ear-flap helmet meeting WBSC safety specifications; a helmet that is cracked, broken, dented, or altered must be removed from play. Rule 2.4.3 requires the catcher to wear a mask, throat protector, helmet, body protector, and shin guards on every pitch, including while warming up a pitcher, given the catcher's direct exposure to pitched and batted balls.
The double first base described in Rule 5.6 exists specifically to reduce collisions between the batter-runner and the first baseman by giving each a separate portion of the base to use on a play at first. Rule 5.10.3.a.ix rules that a runner is not automatically safe merely for reaching a base; rather, if a defensive player with the ball is waiting to make a tag and the runner remains on their feet and deliberately crashes into that fielder, the runner is out, and if the umpire determines the contact was flagrant, the offending player is ejected from the game.
Rule 2.5.1f requires any cast (plaster, metal, or other hard substance) worn by a player to be adequately covered with soft, taped material and approved by the umpire before play, and Rule 2.5.1g prohibits exposed jewelry or other distracting adornments judged by the umpire to be hazardous or distracting, requiring their removal or covering. Rule 2.4.2 limits cleats to ordinary metal or molded types that do not extend more than 1.9 cm (¾ in.) from the sole or heel and bans hard plastic, nylon, or polyurethane spikes at any level of play; youth and modified fast pitch divisions may not use metal cleats at all. Under Rule 3.6.7, an umpire must suspend play immediately in the case of a serious injury that puts a player in danger, regardless of the state of the live-ball action.
