Wi-Fi Assist makes your iPhone more aggressive in jumping off of Wi-Fi and onto 4G LTE.

There are a few exceptions where Wi-Fi Assist won’t work:

  • If you’re already data roaming.
  • If the app trying to use it is in the background. Basically, it only works for apps that are in the forefront and active.
  • Doesn’t work with most third-party apps that download audio, video, or large attachments such as a video app, music streaming service, or an email app that might download big documents or photos.

Why It’s Awesome

Wi-Fi Assist solves this annoying problem in real life: you’re just on the outer edge of terrible Wi-Fi signal, so your iPhone is desperately trying to use Wi-Fi even though it’s too far away to actually go through.

It happens all the time to me when I’m leaving my apartment, just as I’m getting in my car I have just enough Wi-Fi signal for my iPhone to try to use Wi-Fi instead of LTE, but not enough Wi-Fi for anything to actually work. Sometimes I’ve sat for minutes, even driving around the parking lot before my iPhone will connect to the Internet, which is when I need to be playing my Apple Music playlist or navigating. I often resorted to simply turning Wi-Fi off and back on just to get my iPhone to connect to LTE.

Some people don’t like having Wi-Fi assist enabled because it can majorly run up your bill if parts of your house have weak Wi-Fi signal, like this poor kid who ran up a $2,000 cellular data bill. Ouch. Some people even tried to sue Applebecause the feature was enabled in the iOS 9 update without customer consent.

How to Enable or Disable Wi-Fi Assist

It’s incredibly easy to enable or disable this feature if you know where to look.

Settings > Cellular > then scroll ALL the way to the bottom, and you’ll see the switch. Green is enabled, grey is disabled.

You can also see how much cellular data your iPhone has used if you have at least updated to iOS 9.3 or later.

What Devices Can Use Wi-Fi Assist?

According to official Apple documentation on Wi-Fi Assist, any device running iOS 9 or later can use Wi-Fi Assist except the following devices:

  • iPhone 4s
  • iPad 2 (with cellular)
  • iPad 3 (with cellular)
  • iPad mini 1 (with cellular)