Unsurprisingly, it appears the 3DS will be region-locked, just like its predecessor, the DSi.
Nintendo has yet to officially announce any region-related confirmation for the 3DS, but NeoGAF user farnham translated an email from Nintendo of Japan’s customer support stating, “The Region Codes are installed in each games and the 3DS itself…. If the codes don’t match you can’t play.”
The DS and DSLite were region-free, while the DSi and DSi XL were region-locked.

This comes on the coattails of Nintendo president Satoru Iwata’s announcement that the 3DS will not suffer from the software gaps that plagued the DS and Wii.

“It’s important that you be able to supply software with no pause,” Iwata said. “With the DS and Wii, following the titles that were released at launch, the momentum dropped when there was a gap in software releases. We’re making plans so that this type of thing won’t happen.”
If software is released around regions at relatively the same time at a steady rate, region-locking the 3DS isn’t a big issue. But that’s a big “if.” What do you think of Nintendo’s apparent 3DS software plans?