As long as the phone works, it doesn't have to be on any active network. A phone that doesn't have a current network can be used on WiFi as well. If you live in an area with a lot of free WiFi, you could even get yourself a good app that you can make calls and/or texts from and never pay for direct service. If you don't live in a high free WiFi area though, I wouldn't recommend it, as then you can't really be reached/reach out.