Before you start
- This is PC-only. If you play on PlayStation, Xbox or Switch, your save lives on the console and can't be edited or swapped in — this guide won't help there.
- Close Super Mega Baseball 4 completely first. The game holds your leagues in memory while it's open and can overwrite changes you make to the files.
- Back up your save folder before adding anything (the next step shows where it is). If something goes wrong, you just put the backup back.
1. Find your save folder
Press Win + R, paste this in and press Enter:
%LOCALAPPDATA%\Metalhead\Super Mega Baseball 4
Inside there's a folder named with a long string of numbers — that's your account id. Open it; your leagues live in there.
- Files named
league-….savare your leagues. master.savis the game's own list of your leagues — leave it alone.- Franchise saves are separate copies, so adding or editing a league won't touch a franchise you've already started.
2. Add the shared league
- Get the
league-….savfile someone shared with you. If it arrived as a.zip, unzip it first so you have the raw.sav. - With SMB4 closed, copy that
.savinto your account-id folder, alongside your existingleague-*.savfiles. - Keep the original download somewhere too, in case you need it again.
3. Launch and look for it
Start the game and go to Customization → Leagues. If the new league is in the list, you're done — load it up and play.
If it doesn't show up
This is the part that trips most people up, so here's the honest version. SMB4 keeps its own list of which leagues you have, so a league made on someone else's computer won't always appear just from dropping the file in — it has to be registered with your game first.
The community handles that with a separate tool (you'll hear it called the League Import Tool, or LIT). It's community-made — not an official Metalhead tool — and it gets updated over time. Rather than send you to a stale copy with steps that may have changed, grab the current version and instructions from the SMB4 community Discord.
We'd rather point you to the people who keep that tool current than hand you clicks that might be out of date. Ask there and someone will walk you through it — and once this page can link a verified, up-to-date process, we'll add it right here.
Once your league is loaded
With the league in your game you can change it however you like, right in your browser — nothing to install:
- League Editor — edit names, positions, handedness and all eight ratings, or move players between teams.
- Ratings Converter — turn real stats into SMB4 ratings with a tunable formula.
- Roster Updater — apply a fresh roster to an existing league without starting your franchise over.
These run on a desktop and need a (free) sign-in. There's a full rundown, plus how to find and back up your save, on the SMB4 tools page.
New to modding in general?
Honestly, most SMB4 “modding” is exactly this — sharing and editing league files. Keep a backup before you change anything, make one change at a time so you can always undo it, and don't be shy about asking in the community. Everyone started where you are.