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Apple clarifies how Wi-Fi Assist handles cellular data usage in iOS 9

Wi-Fi Assist iOS 9

Buried deep in the Cellular section of the Settings app in iOS 9 is a new networking feature called Wi-Fi Assist that lets your iPhone use cellular data over Wi-Fi during poor connectivity. Intended to remedy those times when your iPhone gets stuck trying to load data on a weak Wi-Fi connection due to range or other issues, Wi-Fi Assist raised a concern for many iPhone users on tiered data plans after iOS 9 was released.

The feature is turned on by default, so users could mistakenly eat up expensive data on a weak Wi-Fi network without realizing cellular data was being used. Addressing concerns that have been raised over iOS 9’s Wi-Fi Assist feature, Apple issued a new support document this week that details how the feature handles certain situations (via Six Colors):


Wi-Fi Assist will not automatically switch to cellular if you’re data roaming.


Wi-Fi Assist only works when you have apps running in the foreground and doesn’t activate with background downloading of content.


Wi-Fi Assist doesn’t activate with some third-party apps that stream audio or video, or download attachments, like an email app, as they might use large amounts of data.


While Apple acknowledges that Wi-Fi Assist may use “a small percentage higher” amount of data for most users, it clarifies that the status bar will signal the change between Wi-Fi to cellular connectivity. Apple also mentions that Wi-Fi Assist works with most (but presumably not all) apps including Safari, Apple Music, and Maps, which can potentially be data heavy.

Wi-Fi Assist can be managed under Settings > Cellular > Wi-Fi Assist.

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  1. beyondthetech - 7 years ago

    I still believe it should be a slider bar, so that way we can adjust our dependency or priority of cellular or Wi-Fi.

  2. PhilBoogie - 7 years ago

    Was it off by default? I certainly don’t remember turning it on. Anyway, I enjoy 10GB/m, so left it on

  3. Rohan Patel - 7 years ago

    Feature is Turned ON by default. It was on when I updatd to iOS 9.

  4. joelwrose (@joelwrose) - 7 years ago

    So far I have never seen this help. I run into situations where my phone either connects to a random wifi network (comcast networks are bad about this) or trying to stay connected when I leave my house and it still kills my streaming music.

  5. Dave Howarth - 7 years ago

    My facebook feed waS exploding last month and people were losing their minds over wifi assist. It was crazy. I kept telling them to try it for themselves before they panicked about over hyped articles online. I told them I had been on the beta for months and while I found a few apps running more smoothly in remote areas of my workplace where WiFi was spotty, the data usage difference was barely noticeable.

  6. granpapa plan w unlimiteless. Keep it on works for me. hehe =)

    • srgmac - 7 years ago

      Same :) Unlimited 4G owns, I get 5MB/s most days and download over 1TB a month.

  7. lmabe10 - 7 years ago

    What’s weird is that you can’t find Wifi Assist when using the new search bar in settings….

  8. Dave Hollingsed - 7 years ago

    How does the status bar indicate it? I disconnected my 3gMicrocell on AT&T and it works fairly well, but not well enough to get exited about.

  9. perks83 - 7 years ago

    I purposely turned this off to keep my data usage down, but I’ve just had a lightbulb moment! “Is this why my phone always drops the call when it’s probably used the WiFiCall feature and I walk out the house and won’t seamlessly switch to cellular without dropping the call????”

  10. Aaron Loy - 7 years ago

    A small %? My arse. More like quintupled my data usage.

  11. moimadeline - 7 years ago

    Within two days of using my new iPhone, I got a message saying I had used up 90% of my data allotment. ! ! ! By the time I got back to the apple store two days later, I had $70.00 in additional data charges. I spent at least half an hour with the apple salesman in the store, and she did not mention a thing, even as she was talking about data capacity in my new contract. Was that an omission on purpose? Does apple have an agreement with Verizon not to warn people? Millions of people getting hit with data overages in the first month of use would be a nice bonus for Verizon.
    Just saying…

    • fistsoffrost123 - 7 years ago

      I can’t believe something like this was even considered. How ridiculous.

      Why wouldn’t you consider instead that maybe the technician you worked with just didn’t know?


Avatar for Zac Hall Zac Hall

Zac covers Apple news for 9to5Mac and hosts the 9to5Mac Happy Hour and 9to5Mac Watch Time podcasts.