Playing Australian Games on an American Nintendo DSi – Region Compatibility Guide
Yes, physically they work. The DSi is region-free for DS cartridges (slot-1). You can insert an Australian (PAL) DS game and it will boot.
Caveats
Language: Game text defaults to English (AU/UK), usually identical to US. Some EU multi-lang carts default to console language (DSi region = US → English).
DSi-Enhanced / DSi-Exclusive titles: These are region-locked (e.g., Pokemon Black/White DSi features, System Flaw). An AU DSi-enhanced cart may not launch on a US DSi.
Online: Nintendo Wi-Fi Connection shut down (2014). Local wireless works cross-region.
Verification
Check the cartridge label: TWL- prefix = DSi-enhanced (region-locked). NTR- = standard DS (region-free).
Test before buying if possible.
For 3DS: region-locked for 3DS/DSi-enhanced games; original DS games remain region-free.