How to put an Apple Watch on a wifi network that its iPhone doesn't know? My college has two wifi networks: eduroam, which uses WPA2 Enterprise authentication and is meant for all of our computers/phones/tablets/etc., and open, which has no authentication and is meant for devices that can't handle WPA2 Enterprise, such as smart TVs and Amazon Echoes. WPA2 Enterprise-capable devices literally aren't allowed to use open, they won't be allowed to connect to the Internet from that network.

My question is, how can I teach my Apple Watch that open is a usable network, given that I can't put my iPhone on open?
I am assuming your iPhone can connect to the open network (but can't get to the internet).

Your iPhone needs to be paired with Apple Watch when it connects to the network — it doesn't work over iCloud Keychain. 

Once your iPhone is on open your Apple Watch should follow. You can then Forget the network on your iPhone and it will remain on Apple Watch.