Why do I need Cellular Data turned on to send/receive MMS?

You also don't understand what it said. Although it is not worded well. but what it means is:

• Send or receive MMS messages. You can still send and receive SMS [with no data connection]
• You can send and receive iMessages (text or multimedia) when connected to a Wi-Fi network.

SMS does NOT require cellular data OR WiFi. SMS goes over the voice signal channel. So you can have WiFi off AND cellular data off and still receive SMS. That's why a billion dumb phones that have no data capability can still send and receive SMS.

You cannot receive or send iMessages or MMS without data. But SMS will still work.

What may be happening is that people who send you iMessages may not have "send as SMS if iMessage is not available" checked on their phones.

Just found this info here:

http://support.apple.com/kb/ht4146

part of link copied below, note the line about not being able to receive SMS without cellular turned on! I don't understand why!

Understanding cellular data settings

You can temporarily turn off cellular data to prevent applications from using the cellular network connection to send or receive data. If you turn off cellular data, you will be unable to:

• See the cellular data icons in the status bar (for example, LTE or 3G).
• Send or receive MMS messages. You can still send and receive SMS, and send and receive iMessages (text or multimedia) when connected to a Wi-Fi network.
• Retrieve or listen to new Visual Voicemail messages. To retrieve messages, enable cellular data.
• Use Personal Hotspot.

MMS is a hybrid text message where the text portion is sent over a cellular voice channel (as with SMS texts) but the graphic data (picture or video) is sent over a cellular data channel. With AT&T, if you have wifi calling enabled, MMS can use your wifi data connection. But without the active wifi calling feature, every cellular service provider on the planet will require cellular data be enabled in order to send or receive MMS messages.

I am having the exact same problem with my 6s and thinking mobile data wasn't always a thing and everything was fine but now we NEED IT all of a sudden so sorry this probably doesn't help but just so You know your not the only one

aai92- I am having similar situation. Ever since I updated to iOS7, then I traded up for an iphone 5c, I've been either going over on my data plan or coming very close to over. I've also called and gotten nowhere. I've become obsessed about this. I've turned off apps that are using cell data, closing out every app after using so its not "running in the background", etc. I just recently realized it could perhaps be MMS, but this was never the case before iOS7/5c. My wife sends me texts from her email at work. This is considered an MMS and I can not receive thses or respon to these particular messages without cell data truned on. You'd think these messages would be covered under my unlimited texting plan. The issue I have is my "data usage" has not increased since Oct/Nov and all of a sudden it has?!? This doesn't make since. When I call they blame it on apps being open or auto back up turned on or they cant answer this for me. I have auto back up turned off and I've always been told if apps are open its only for multi tasking but there's not actually. The other thing is I can't believe others are being so diligent about turning cell data off for apps, watching their usage like a hawk, closing out apps, etc and they're not going over. Is this a widespread issue. Please help!!!!

Look here, from Apple:

The following table shows the requirements and capabilities of Messages on iOS.

See what it says about MMS? That answer your question.

This post has been quite helpful, as I went through something trying to figure out why I couldn't do this. Now I understand.

Here's my question: if I have 3G off and someone sends me a photo, will I get it once i turn 3G on? The guy at the Verizon store told me I should and to call customer service. Now I'm not so sure.

I have the iPhone 4.

3G is the connection type.

Celular Data is the transfer method. It means its using the Cellular Data or Carrier's internet connection to transfer.

The connection can be 2G, Edge, 3G or LTE/4G each method is faster than the previous one.

Turn on 3G or LTE/4G and the transfer is faster than through 2G, Edge, or 3G.

Basically you can have cell data at different speeds. Depending on the connection type available.

The Phone will usually just connect to the fastest network available that it can. For the most part its not something you choose though. Its something the phone selects based on what's available in the area. Though you can prevent it from connecting to 4G/LTE.

If you turn off Cellular Data, it simply won't transfer anything that requires an internet connection, but the Phone / voice connection will still be at whatever connection type it can find. However the logo won't show up because its just using the voice connection.

Ok look at it this way.. if you turn off your cell data on your iphone, forget is it 3g or 4g or lte or whatever. if you flip that top switch to off, the cell data symbol next to the signal strenght bars will go away.. Meaning your phone is basically dead in the water except SMS and phonecalls. iphone with no cell or wifi data is kinda like a brick but i am sure you know that. I am sure you have your reasons for doing that..

realisticly if you get an MMS sent to you while you are off the cell data network, it should come in once you turn it back on. Maybe not instantly but in next 30 min or so. Same thing happens when you go into airplane mode and disable all radios. Once you exit airplane mode all your voicemails and SMS messages come in. imessages do not go thought when data or all radios are off, they instead get rerouted and sent as SMS and pop up on your phone once you re-enable the radios.

if if were you, you are better getting off the unlimited text plana and pay more for some more data. with imessage and so many freaking iphones out there you wont need that many messages. every blue message is free remember. you only pay for green messages.

The reason I leave the 3G off is to save the battery. I understand the concept you are presenting, however, if I send myself an MMS to test it, with a photo, then turn the 3G on, it doesn't come through. Not immediatley, not in 30 minutes, not ever.

So you forced to use 3G with cellular data.

I can disable 3G to save battery and avoid big upload/download by accident but I'm able to sent/receive iMessage and generally be online with GPRS or EDGE. When I need to be fast I enable 3G.

Yes, I suppose that is true. What version of the iPhone do you have. I'm curious, since our options are different.

I still can't get a handle on whether photo messages should be saved for me when I turn on the 3G.

What makes this exceptionally sucky is the fact that carriers sell Unlimited messaging plans which are supposed to support image and video MMS. I pay $30 for that. My wife has a 3GS that shares my unlimited texting feature, but without a data plan, she can only send txt. On an android device without data, she was able to use cellular data to send images. I'm thinking of canceling my unlimited txt feature, but now AT&T doesn't even have a 'limited txt' option.

Shame on all parties for this.