Mario Super Sluggers on English Wii: Region Compatibility Explained

Yes, the main release works.

• Mario Super Sluggers (2008, NTSC-U/J): Region-free on Wii. Plays on any region Wii (US, EU, JP, KR) via Gecko OS / Priiloader / USB Loader GX (homebrew) or natively if same region. Note: Official disc channel may reject cross-region; use homebrew loader.
• Mario Superstar Baseball (2005, GameCube): Region-locked. Needs FreeLoader / modchip.

Crucial Distinction

There was no Japanese-only "Mario Super Sluggers" in 2005. The 2005 GameCube title is Mario Superstar Baseball. Super Sluggers is the 2008 Wii sequel.

If you have a Wii disc labeled "Mario Super Sluggers", it will work on an English (PAL) Wii with a homebrew loader (e.g., USB Loader GX). Original disc channel will say "Cannot read disc" on cross-region.