What is a Nintendo Network ID?
Nintendo Network ID is a unique identifier made up of 6 to 16 characters. NNIDs were used for online features (such as online multiplayer or interactions) prior to 8 April 2024.
If you have connected your Wii U to the Internet, we strongly recommend you register the same Nintendo Network ID on Nintendo 3DS.
For more information, please visit our Nintendo Network ID Support section.