iPhone 5 confusing Wi-Fi data with Cellular?

If I were you I would take the phone to a Verizon store and ask them to explain the discrepancy. Maybe something's wrong on there end.

A feature of iOS 6 is that when your Wifi connection isn't providing Internet access (say, you're on the local network but can't get through to the Internet), the phone gracefully falls back on the celullar data network. Prior to iOS 6 you had to manually disconnect or turn off Wifi when your local network wasn't providing Internet access.

It appears you've just stumbled upon a significant downside to that feature, in that if it falls back silently onto the cellular network, you can burn through more of your quota without realizing it.

Are you sure about that? Cellular + wifi was on the last iOS 6 beta but the articles I've read say it didn't make it into the final version.

Wow, glad I saw this post. I've been posting in the iPhone 5 WiFi issues threads for protected networks for a little while now. This post explains the "flaky" WiFi access people are having on WPA/WPA2 networks. I just took a look at my cellular data usage for today: 122MB! It appears that the flaky network access I was getting was actually LTE gracefully taking over.

I believe one Apple engineer said "LTE can even be faster than your home wireless connection." That's great Apple, but I would at least like the opportunity to use protected WiFi on my iPhone.

Don't be so sure about the "gracefully taking over" part. Cellulare Plus Wifi, the feature you are talking about, was in iOS 6 beta 4 but the setting for this is no where to be seen in the final iOS 6 release, there is no mention of this in the iOS 6 user manual and articles on the web have commented that this feature was removed from the final version. I see no evidence that this feature is in the final version of iOS 6.

Just tested your hypothesis.

Started out with 122MB cellular usage and enabled WiFi for my protected network. Signal was good, but data connection was spotty at best. Started up the YouTube app and tried watching videos. Again, there was little to no loading of videos. All the sudden, my connection was great. My status bar still showed me connected to WiFi, not LTE. I waited for an entire 3 minute video to load, then I re-checked my cellular usage: 125MB!

I have tested this several times now. It's a little more than a coincidence if you ask me.

All I can say is that it isn't documented anywhere and the setting from Beta 4 (see image below) is not on the phone. In only says Cellular Data.

My theory:

iOS 6 GM was seeded on September 12th. I'm assuming that's when they removed the WiFi Plus Cellular feature. Apple had probably already packaged millions of iPhone 5s by that time. I'm thinking the version of "iOS 6" running on iPhone 5s is more like "iOS 6 beta 2 or 3".

I am having same issue. Cellular data count is going up, even though I am actively using phone on wifi N from my AP extreme router... Went from 1 --> 50MB with two YouTube vids just now.. We need official answers.. To me it seems apple took out the settings control of wifi plus cellular, but for "user experience" left it active behind the scenes!!!

My iOS build is 10A405 so I know it's not a beta version... GM was 10A403

I am having the same issue. I am going to call Verizon this morning. We purchased two new phones and only used them on LTE for about an hour while we went to dinner. All the other time we were in our house with WiFi indicated on the phone. I checked by usage after finding this post, 318 MB used on the new Verizon shared data plan. Each phone used over 150 MB. The only thing we were doing was surfing the internet and sending iMessages while we were at dinner. I looked back at the items that I was doing in the house and I remember after activating the phones and doing a backup that each phone had about 40 apps that needed updated. I believe that 150 MB per phone was due to this period of time.

This is a great example of Apple and Verizon not informing the consumer of a money making feature on the new phone. Verizon promoted the shared data plan to me in the fact that by using WiFi when available would mitigate any overage on data. Apple doesn't inform the consumer that there is a cellular over WiFi feature as there was on the Beta version. I sure hope this gets fixed because I have only once in the last two years ever used 150 MB of data in a single day. We normally only use 1.5 GB in a billing cycle. UGH!!

I called Verizon and they did not know of this issue. I was informed that I would be called back after they did some research and also contacted Apple to ask if there is a known issue. They said they were not able to credit any of the data back at this time, so I am stuck with that. Currently I am on airplane mode with wifi turned on so that I can use the phone in my house. What a crappy way to use the greatest smartphone Apple has to offer!

There's also a new option to just disable cellular data w/o airplane mode (useful because airplane mode turns off Bluetooth and GPS)

Go to General -> Cellular -> Data to OFF

To the earlier poster who speculated that they removed te graceful fallback feature, I honestly don't know--I can't test it here. But anyone should be able to by unplugging their upstream (modem Ethernet) from their router and then trying to get to, say, a web page in safari while on the wifi network.

That'd certainly prove it.

Contacted Apple Tech Support and their fix is to turn off all the apps running in the background because one of those could be using cellular data even though you are connected to wifi. So as I said to the rep, this confirms that cellular is being used while connected to wifi. The response is no, this would only be if that app relied on cellular and in that case yes it would use it, sounds fishy to me.