Region Free with hardware modification only (Though some titles are Region Free)
Alright, this is a confusing one, so bear with me. The 32X uses the Mega Drive it’s connected to to determine its region, but at the same time it has its own NTSC/PAL setting in that the hardware clock sync is different between the two standards. Confused yet? Let me break it down a bit more. The 32X has 2 variants, PAL and NTSC. The Mega Drive has 3 region settings: EU, US and JP. For a 32X game to successfully boot, one of the following 3 combinations has to be met: NTSC-USA for American 32X carts, NTSC-JP for Japanese carts, or PAL-EU for European carts. No games will work with the other 3 potential combos (for the record: PAL-USA, PAL-JP and NTSC-EU).
Adaptors can switch the region of the system around, but they cannot switch around the 32X’s variant; so for example if you stuck a converter cart in the chain somewhere and attempted to boot an American 32X title on a European 32X and Mega Drive you would end up with PAL-USA, and the cart would not start.
Unfortunately, the only way around this is modifying the 32X – and honestly, it’s a lot less bother to just find an American or Japanese 32X on eBay. When plugged into either a Japanese or American Mega Drive respectively, the NTSC 32X (remember the 32X’s variant is common for the two) will boot JP and USA games respectively. This trick also means if you have an unmodified NTSC (American or Japanese) 32X and a USA <–> JP region-modded NTSC (again American or Japanese) Mega Drive, then this will play all NTSC 32X games.