Manage iOS automatic connection to public Wi-Fi I use Skype to make some international calls. This works well if I am at home/office and connected to Wi-Fi.

However if I am on move, I prefer to turn off Wi-Fi to prevent connection to public Wi-Fi networks so that it won't affect my ongoing calls.

Sometimes after calls I forget to turn on Wi-Fi and start using some other app which can consume substantial amount of data.

Is there is any way to disconnect Wi-Fi for just a few minutes (the estimated duration of the call)? Or to force app calling features to use cellular only?
Rather than manually managing when you are connected to untrusted WiFi access points, you should consider setting up a VPN connection that is automatically enabled when you connect to WiFi.  That will protect your data - even when on a public WiFi network.  At that point, you don't need to worry as much about whether WiFi is on or off.