The NSFPL recognizes the Amateur Softball Association (ASA) as the authoritative national governing body and follows ASA rules on the field, with the following adjustments for 2019:
- Game length will be either 6.5 or 7 innings in length depending on who is ahead or two hours drop dead,
- Maximum number of runs per inning will be five and at 10U only no drop third strike.
- Coaches still have the option to adjust other rules as long as both coaches agree and the umpires are informed prior to game time.
Coaches may obtain a copy of the rules by registering their team with the ASA.