Q: The iPhone 5 uses Cellular Data over WiFi?

My iPhones have NEVER switched from cellular to WiFi and always use cellular if it is not turned off. I have to turn cellular data off, and Apple makes sure I have to go through several windows to do that, in order to discourage me from using less data.   If Apple and the providers (FWIW I use T-Mobile) didn't want that, they would make it easier for me to save data usage by, at the very least, offering an App for me to turn off cellular data easily--but there is no such thing. 

I have virtually everything tuned off or to manual, no fetching, notices, etc. and have done that through every iPhone I have had (this is my fifth). 

In addition, this iPhone 5 signs me out of virtually every website I use, and I don't like signing in all the time--I just want to go to the pages I want. 

So, I plan to return the iPhone 5 and revert to my iPhone 4.

I wonder if this is operator-specific. My iphone is not linked to an operator and has always prioritized WiFi connectivity over 3G

I am so happy I found this discussion!  I was starting to go crazy.  The iPhone 5 is my first iPhone ever and the IT department at work has been struggling to figure out why my data usage is so high compared to everyone else with an iPhone 5 in the company!  This past Sunday I racked up $500 worth of data while connected to WiFi at my house!!!  I think it is a glitch with certain iPhone 5's because other people in my office don't have this issue!  I ordered mine directly from Apple.com the day it was available.  I have been into my cell phone service provider and he has looked over everything on my phone and he can't understand what is happening as my usage is very typical.

They are ordering me a new iPhone 5. I will repost if I see a change with the new phone.  Gah!!! So frustrating!!!

I don't understand "not linked to an operator" and would like to.  Could you elaborate? Perhaps it's semantics and you meant provider or phone company or a similar word (and maybe that is called "operator" in other countries?).  I would love for my phone to work as yours does!

That's absolutely crazy, Rita!  I was upset when, for the first day, I racked up 25% of my allowable data minutes while Wifi was turned on at MY house.  There's no easy way to turn off Cellular Data and I think Apple needs to fix this with a software update.  It should be easy to toggle when I turn on my iPhone, just as it is easy to get a message or any other notification.

Further, I see that whenever I'm at home and accessing the internet, there is a cellular data charge, even if it is a minor charge. It simply should NOT be happening.

Another thing, I use Bluetooth in my car, so, whenever I'm NOT in my car, my phone is perpetually searching for bluetooth and the battery goes down PDQ.  That's another thing Apple needs to fix. Have a way to STOP searching for a Bluetooth Signal (even a toggle would be great) a way to STOP searching for a phone signal (for when I'm out of signal area, e.g., on sailboat) and toggle turn off cellular data.

These things seem pretty basic to me.  And I don't understand how Apple profits by this, or creates profits for it's corporate customers or the world (e.g., AT&T, Sprint, Verizon, T-Mobile) or how overusing cellular data is being a responsible entitiy.

That'd be great.  Unfortunately, Apple forgot to build in an easy toggle for this and you must go through several windows to turn it off.  And then, several windows to turn it on again.  Same thing for Bluetooth.  Notice how fast your battery drains.

This is an Apple problem. It happens with all providers.

I hate to be the bearer of bad news but I switched to Verizon in February from AT&T, got the new iPhone at that time and 4 months later all of the problems people are describing with spikes in data has happened to me.  I have not changed the way I use the phone, loaded new apps, I'm connected to WiFi when at home and work which is most of the time...yet I managed to go from less than 1 gb consistently per month to over 5!!  The Verizon customer service has not been able to help and has given the standard, you must not be connected to WiFi or you must be doing something different.  I have gone through and made changes to the iPhone as has been suggested in many postings and will see what happens but my feeling is this is an Apple issue, not a carrier issue. 

My husband has an Android and my son a Samsung Galaxy and neither of them have had these issues and they are on the same plan.

iPhone 5 Data overage problem solved!!!

I had the exact problem on Verizon with my wife's iPhone 5. Started using massive amounts of data. Tried 3 replacement IPhone 5, hours and hours of troubleshooting on the line with Verizon etc... etc... etc...

Finally fixed the iPhone 5 problem! I made Verizon take back the iPhone 5 and give my wife a Droid Razr Maxx HD, the same phone I have.

Now I have 0 problems with data overage, I have actually reduced the data plan down to 4GB which is plenty for my wife and I.

I am having this problem. This past Friday, my phone downloaded 1.2 gb of data in less than 20 minutes. While I was in a meeting and the phone sate on the table in front of me unused. The cellular data was off like it is all of the time now because I kept getting charged for cellular data while on my home and work wireless. How is that even possible? Even in the middle of the night while I was asleep and all applications were off. Verizon is telling me it is an Apple problem; Apple says it is a Verizon problem. So in 24 hours I ran through 1.85 gig of data. I now have the phone turned off because just turning off the cellular data clearly doesn't work. Verizon refuses to credit me, the "Senior Advisor" at Apple who promised to help me did not. I have no recourse but to switch back to a spare phone with no data package or I risk running up an even more outrageous bill. It's bad enough the iphone 5 runs through battery power in less than 10 hours with light use. It's bad enough I can barely hear the person on the other end of phone calls. It's bad enough the phone has zero storage capacity because of all the bloat ware Apple shoves down our throats. It's bad enough that every time Apple "updates" the iOS I can't use the phone until I reset everything and start over. Just sick and tired of this pOS. I agree with the poster who found the REAL solution to this problem - exchange the iphone for an android phone.

I understand. As far as I'm concerned this is an Apple design problem.  Verizon doesn't control how the iPhone works.

You have to turn off all the features that make the iPhone a "smart phone" so you end up with a $700 dumb phone.  Apple has a big think-tank and they have the expertise to develop toggles to easily turn off and on various features that are drains.  But it doesn't.

BTW, a big drain is Bluetooth.  If you use it in your car (as do I) it's great. But when you leave your car, it will spend all the time searching for a BT signal, unless you specifically go in to the BT page and turn it off.  There should be an easy toggle.

This VERY long thread points to major gap in iOS--no ability to track cellular usage by app.  No doubt with this many people experiencing problems there is probably more than one root cause problem.  And some of them are probably carrier-caused and some of them are probably bugs in iOS and some of them are user-induced.

Considering most users are paying directly for the cellular bytes they are using (and paying indirectly in crappy battery life)  to me it is an unforgiveable ommision of Apple to not include tracking and better control by app.  And unforgiveable for carriers to not have demanded tracking ability to help their customers manage their usage. It looks like Apple has finally figured this out--iOS 7 beta previews show cellular usage by app and control of cellular data by app will be available.

Usage tracking apps that could monitor by app were available for a while but Apple put a stop to them because the way they were accessing internal data.

Earlier this year I purchased Onavo Count to track my app data usage, but it turns out a large chunk of my usage did not come from 3rd party apps. There were a series of internal programs that were displayed (e.g., run by the iOS, not me) but Onavo was restricted from showing how much data was actually used. By process of elimination, I determined those internal apps accounted for about 50% of my data usage. And I have no control over them. I gave up months ago trying to figure this out. My employer requires I use an iPhone and connect to their mail server, and they pay a large enough portion of my bill to justify an unlimited data plan, so I live with it. But I use 5 times more data than I used to, despite insanely vigilant attention to turning off cellular data when connected to WiFi, shutting down apps, location services, notifications, etc. etc., I could not get my data usage anywhere near my old rates. There is no doubt in my mind this is Apple's problem, perhaps exacerbated by cell carrier or app.

I have been reading this thread for quite some time and I too am very frustrated with this problem. I just can't get a handle on it; my iPhone 4S is fine (it stays put on WiFi at home) but my daughter's new 4S keeps switching to cellular. She is on a 300 MB plan with AT&T which rapidly gets depleted (she keeps forgetting to look at icon in upper left to make sure she's on WiFi at home). On top of that, I have Smart Limits set on her account (which AT&T charges $5/month) which is supposed to stop her cellular data access at the 300 MB mark. Of course, during her first billing period, she happily sailed past the dataplan stop point and AT&T charged me $20 for another block of 300 MB. Happidly, then credited me the $20 when they saw the SmartLimit didn't do what it was supposed to. We'll see what happens this time. I've done a lot of what is suggested here, rebooted the phone, etc. Because this seems to occur with several different carriers, I suspect that this is completely an Apple issue.

Yes, I believe it's an Apple design problem.  FWIW, if you can get T-Mobile in your area, it can be much cheaper long-run.  I've had T-Mobile for years, and have used several iPhones with it.  Of course, that doesn't fix the switching problem.

A T-Mobile rep told me that I don't get charged more if I go over my minutes, but that the service "slows down" I don't want to find out.

http://www.forbes.com/sites/stevenrosenbaum/2013/05/28/att-and-apple-battle-over -data-leakage/

This issue is deplorable. Please take a moment and read the above link. I found this after 3 hours on the phone with AT&T and 3 hours with Apple. Everyone was quite polite and civilized but I know if I can find this in a google search these people can as well. If neither AT&T or Apple will listen or make a change it is time to call for a class action.