It seems forever. The info came from nintendo saying forever
GBAtemp.net - The Independent Video Game Community
xtheman
AshleyCummings
my 3DS is banned but my NNID is not how in the dang world do I get it off my 3DS and into my 2ds?
AshleyCummings
I can use my NNID on my WiiU all fine and dandy ..
xtheman
If your 2ds isn't banned you can transfer a file from the 2ds to the 3ds and unban it. (But no eshop and co)