Apple explains how Wi-Fi Assist works

Apple has posted a support document, “About Wi-Fi Assist” which explains that with iOS 9, you can use Wi-Fi Assist to automatically switch to cellular when you have a poor Wi-Fi connection.

How Wi-Fi Assist works
With Wi-Fi Assist, you can stay connected to the Internet even if you have a poor Wi-Fi connection. For example, if you’re using Safari with a poor Wi-Fi connection and a webpage doesn’t load, Wi-Fi Assist will activate and automatically switch to cellular so that the webpage continues to load. You can use Wi-Fi Assist with most apps like Safari, Apple Music, Mail, Maps, and more.

When Wi-Fi Assist is activated, you’ll see the cellular data icon in the status bar on your device.

Because you’ll stay connected to the Internet over cellular when you have a poor Wi-Fi connection, you might use more cellular data. For most users, this should only be a small percentage higher than previous usage. If you have questions about your data usage, learn more about managing your cellular data or contact Apple Support.

You can use Wi-Fi Assist with any iOS device with iOS 9 or later, except for:
• iPhone 4s
• iPad 2 Wi-Fi+Cellular
• iPad (3rd generation) Wi-Fi+Cellular
• iPad mini (1st generation) Wi-Fi+Cellular

Turn Wi-Fi Assist on or off
Wi-Fi Assist is on by default. If you don’t want your iOS device to stay connected to the Internet when you have a poor Wi-Fi connection, you can disable Wi-Fi Assist. Go to Settings > Cellular. Then scroll down and tap Wi-Fi Assist.

Items of not about Wi-Fi Assist
• 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.

Source: Apple Inc.


  1. WiFi assist is not available in iOS 9.0.2 on my iPhone 6s using Optus carrier in Australia. In fact using search in system settings, typing in ‘assist’ won’t show anything remotely similar.

    Curiouser and curiouser quoth Alice.

    1. Correction: it is buried right at the very bottom of all the apps using mobile data. Would if not be smarter if it was in the top selection of options? Well anyway… it is there. BTW Australian users note the submenu in Settings is Mobile – not Cellular

  2. Wow, that’s all great.

    Hey, Apple, how about the ability to prioritize networks like in OS X?

    That way, when you get home it switches from the roaming cable wifi to your home network, and when you get to work it logs into the network for your office and not the slow one you occasionally have to use for secured business.

  3. I can tell you how it does not work on my iPhone 6 with ATT: I hit speaker and I’m talking on cell, then the signal flickers and I get shifted to Wi-Fi Assist. And I get dumped from speaker. Or maybe it’s vice versa, because I’m always trying to do something else with my eyes and hands, THUS SPEAKER. Let’s get this fixed in 9.1, eh?

  4. This sounds a lot like the “Sprint Connection Optimizer” which does exactly the same thing. I have it turned permanently off on my phone now though, it was annoying to keep finding my phone connecting to cellular data every time I went out of range of my regular WiFi areas. Now if Apple improved on it by turning cellular data once a strong Wifi signal was detected, that would be useful.

  5. For newbies: Why you’d want to turn Wi-Fi Assist OFF.

    Because accessing the Internet via a cellular network eats money, eats your bandwidth allotment, and is potentially slower than your current Wi-Fi connection.

    If you’re paying for unlimited bandwidth at a fixed price, the only down side might be the slower connection. Thankfully, at long bloody last LTE Advanced (aka REAL 4G) is supported in the iPhone 6S series and is now being gradually rolled out across the world.

    [I say ‘at long bloody last’ because the LTE Advanced standard and supporting circuitry have been available for about over three years!]

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