If you’ve been using up a lot of cellular data on your iPhone recently, one particular app (such as one that streams video) might be using more than others. Here’s how you can prevent an app from using cellular data at all.
First, open Settings by tapping the gear icon.
In Settings, select “Cellular.”
Under Cellular settings, scroll down until you see the list of apps installed on your iPhone. They are sorted by which apps use the most data. Locate the app you’d like to prevent from using cellular data. You’ll see the app’s cellular data usage listed just under its name.
To prevent that app from using any cellular data, flip the switch beside it to the off position.
After flipping the switch, the app will work when you’re connected to a Wi-Fi access point, but it will act as if it has no internet access when your iPhone is connected to cellular data only.
Repeat with any other apps you want to keep off of the cellular data network. Your mobile phone bill will thank you!
