Q: The iPhone 5 uses Cellular Data over WiFi?

My wireless router accesses 3 computers, 2 phones, a Wii, and an iPad, but I have not had any issues with my phone using cellular data once I turned off the LTE. When I turn off the LTE it reverts back to 3G and always uses our household wireless, as far as I know. I just checked our monthly useage (which only has 6 days left in our cycle) and my wife and I together have only used 200mb, and I watch netflix on my phone all the time while I'm laying down at home. My phone is faster with the LTE turned on, but not enough that it makes a big difference to me. My wife and I only have 1GB of data between the two of us to use every month, so we choose not to have LTE turned on because in our experience LTE uses up data VERY fast. 

bannana77 - Thanks for the data. That's good to know. That's the most helpful advice on this issue I have had in all my searches. Still not 100% happy with that solution. But, it sounds like the best option until Apple decides to fix this flawed logic. We will give that a try. 

Bannana77: Is it the option that says Roaming?

When I look under Settings->Cellular Data, the second option is Roaming.

When in "Cellular" the 2nd option down for me is "Enable LTE"

Odd. What OS are you running? That option is not available on my sons phone. His is a 5c.

I'm running 7.0.6
I have a 5s

Did you try turning on the cellular data? When the cellular data is turned off the option for "Enable LTE" is not there underneith it on my 5s.

The past two nights between 2-3 am I've been charged for going over my data plan?!?! The problem is I sleep at night AND MY PHONE IS CONNECTED TO WIFI?!?!?

The 2 - 3 am period is not when you are using it, it is when it is being billed.

For some reason, I just don't have the problem.  I have an iPhone 5 running the latest iOS. I use AT&T's 300 MB plan. LTE is enabled but the phone is almost always used on WiFi so data usage is minimal.  With 5 days left in the billing cycle, I have only used 31 MB.

Bannan77: That worked. When I turned the cellular data signal back on, it gave me the option to turn off LTE. Our billing period started new today. We are going to give that a try and see how that goes while I monitor his data usage closely.

This past month, he used 3.75 GB of our 4GB data plan that is shared by 3 phones in 8 days (before we discovered the issue). After discovering this issue, we had him turn off cellular data while at home and connected to Wi-Fi. Low and behold for the entire month, all 3 phones only used 4.25GB.

THanks for all your help!

Allan: If you are just doing web surfing, email and occassional games/apps it generally isn't a problem. My husband and I use our phones all the time and only use very minimal data as you described. My son, however, is constantly streaming videos....CONSTANTLY.. We have had extensive talks with him about not doing this when he is away from the house and on the cellular data and taught him how to make sure he is on Wi-fi and he obeys these rules. In fact, when other kids are streaming videos he takes the time to educate them on what they are probably doing to their parents data plans.

So, we were shocked when we got the text message 8 days into our billing cylce that said we had used 75% of our 4GB plan. His phone was constantly connected to Wi-fi and said it was connected. His phone hadn't even left the house in that 8 day period (because I won't let him take it to school). So, you never even notice that it switches over. We performed tests while it said he was connected to wi-fi and watched our data usage go up on our carriers website.

So, your phone is probably doing the same thing. You just around using enough data to even notice that it is happening. We wouldn't have noticed it either if was using it as much as my husband and I do.

The other thing to consider is that even if your LTE is enabled doesn't mean that you are necessarily always getting an LTE signal from your carrier. If your get weaker signal inside your house or live in an area that the carriers signal is weaker, then your cellular signal may only be connecting at 3G at that time. Therefore, when you are connected to Wi-Fi, the Wi-Fi signal is winning out the battle for speed and there is no problem. Additionally, even if you are getting an LTE signal inside your house, if you wi-fi router is newer and not being overloaded like ours is, then you also may not have an issue. Our Wi-Fi signal is bogged down with 3 laptops, a few tablets, an ipod touch, 3 smart phones, an Xbox 360 and a PS3. The bandwidth is that the single iphone 5 device is getting would never win out on an LTE signal with all that going on.

Allan,

Yes, you do have the problem. 

You just said you used 31MB of cell data while using wifi.

You have the problem - just like all iPhone users.

I upgraded to iOS 7.0.2 while on wifi. 

My iPhone 5 on AT&T used 1.6MB of cell-data.

There is very obviously a flaw in iOS 7 that needs to be fixed.

I did not say I used 31MB while using WiFi.

I do use WiFi at home and at coffee houses, etc.

But my 31MB of cellular data was used when driving or walking around, or in other people's houses, when I would use the iPhone to read news, look at maps, etc.

Allan,

I apologize, I mis-read your post.