You ever been in this situation? You're casually browsing the web on your iOS device and you see the wireless symbol in the top left hand corner change to a cellular connection?
If so, then it's because your iPhone/iPad still has Wi-fi Assist turned on in your iOS settings.
So what is Wi-Fi Assist? Put simply, your device will always prioritise the strongest signal if this setting is enabled. When your wireless signal strength drops to the point where a cellular reception is going to provide a faster experience, then you will automatically switch over to your data plan.
This is great - as long as you are on a data plan that you are comfortable with. If, however, your allowance for data is restrictive, you may wish to tweak your settings for each application or, if you prefer, disable Wi-Fi Assist completely.
Preventing Apps from Using Cellular Data
- Navigate to Settings -> Mobile Data (I believe this is Settings -> Cellular in the US/Canada)
- You will see a list of applications with toggle switches on the right hand side. Switch off the apps you wish to restrict from using mobile data.
Turn off Wi-Fi Assist
If you only have preferred applications accessing mobile data, then I would encourage you to keep Wi-Fi assist enabled. However, if you would like to turn the feature off completely, navigate to Settings -> Mobile Data and scroll to the very bottom. Switch the toggle switch off.
You will notice that there is a usage figure for Wi-Fi Assist, as well as all of your other applications to allow you to track exactly how much data this feature is consuming. To reset these statistics to today's date, simply press the Reset Statistics button.