- In Little League and other lower levels, a regulation game consists of just six innings. The game is official if four innings have been completed, with three and a half innings comprising an official game if the home squad is leading when the game is called for whatever reason. Junior League, Senior League and Big League baseball--the upper levels of Little League Baseball that have players ranging in age from 13 to 18--play seven inning contests with a game official after five innings, or four and a half with the home side in the lead.
- The distance between bases varies at the different levels of Little League Baseball. In the lowest level, which is called tee ball, the bases are just 45 feet apart, while at the Little League level the bases are 60 feet apart. In the upper echelons of Little League the bases are the normal 90 feet apart. The pitcher's mound is 46 feet from home plate in Little League but goes back to the regulation 60.6 at the higher levels, just like it is in the professional leagues. An outfield fence on a Little League field can be no closer than 165 feet from home plate; this distance stretches to 300 feet minimum on the Junior, Senior and Big League playing fields.
- A base runner cannot leave the base he occupies until a pitch has reached the batter. This is much different from regular baseball rules, which allow a runner to take any size lead desirable prior to the pitch. Little League rules also state that sliding head-first into a base is not allowed, except for runners sliding back into a base that they have previously been on. On tag and force plays the runner has to try to avoid contact with the fielder. This is encouraged at the upper levels, but is not mandatory.
- In the lower levels of Little League, a batter is out on a third strike regardless of whether the catcher holds onto the baseball or not. This regulation though is not in effect in Junior, Senior and Big League Baseball. The traditional rules of baseball apply in these upper levels, meaning that on a dropped third strike the batter can try to advance to first and must be thrown out at that base or tagged. However, if first is occupied with less than two out, the batter is declared out and cannot advance.
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Each player on a roster must get up to bat at least once in a Little League game and must play defense in the field for at least one inning. This mandatory play regulation does not apply for Senior and Big League Baseball, but is strictly enforced at the lower levels, with any manager in violation of the rule subject to a suspension. If a game has to be called for weather or darkness before six whole innings can be finished then the rule is waived, with no repercussions if some players don't make it into the game.
There are also very strict pitch counts in effect at all levels, with the aim to protect a youngster's arm from throwing too many pitches or from pitching on consecutive days. These numbers vary from level to level.
