I've set up internet on my Wii U but it isn't working?

These are some of the steps I took to troubleshoot my own Wii U, from very early on I noticed the WiFi-connection being lackluster on the Wii U. It probably doesn't help that the Wii U is continuously streaming an HD-feed to the GamePad at the same time.

Establishing a connection

Nintendo supplied a simple guide on how to connect to the internet or follow the steps laid out in DarkWoffle's answer.

• The Wii U can have problems keeping a connection when there's something touching (or lying on top of) the console. Even with my router within reaching distance, it just wouldn't connect.
• You can test the internet connection without a TV! Accessing the Settings only requires the screen of the GamePad. If you're having trouble connecting, find a good spot closer to the router/modem and try connecting again. This way you know if distance is the problem. (I also do this if I want to speed up my download of a 17GB-game).
• For any serious online gamer, or anybody having trouble with the internet connection, I recommend the Wii LAN Adapter. Ethernet is way more reliable than WiFi.

Fixing a problem

Got an error code? Use the Error Code Lookup

There are more specific problems known with the Wii U that I'm not going to explain here, those require a more in-depth guide. In any case, you can contact Nintendo for additional support.

First, it's always handy to check out Nintendo's Network Maintenance Information & Operational Status page to see if the Wii U's network is either down or under maintenance. If everything checks out there, take a peek at your Wii U's network connection and make sure everything operating per the norm.

1. From the Wii U menu, open the System Settings app.
2. From the Internet page, tap the large Internet button.
3. Tap the Connect to the Internet button.
4. Press X, or tap Connections in the upper-right corner of the gamepad.
5. Tap your current active connection from the list.
6. Tap the Connection Test button to ensure that you're connected to the Internet.

If your Wii U fails the connection test for some reason, grab another device on your local network and attempt to connect to the Internet. If other devices can't connect, it's your network! Try rebooting your router and try again.

However, if other devices on your network can connect, then your Wii U is probably the issue. Either edit or delete and re-add your connection to ensure that your password, IP, and proxy settings are all correct.

If on the offchance your Wii U passes the connection test but continues to fail connecting to Splatoon, it's probably just the Splatoon servers specifically.