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Accidental MMS Sending and How to Avoid it.

by on ‎03-11-2016 16:03 - last edited on ‎24-07-2019 17:48 by Community Manager (29,478 Views)

Hopefully this guide will help with understanding why sometimes you may inadvertently send an MMS (chargeable) instead of an SMS (usually free from allowances).


First we need to understand the difference.


An SMS is a normal text only text message (short message service).

An MMS is an SMS that contains a picture, short video clip or any type of “media” (multi media service).


One standard SMS is 160 characters. Most phones have a character count (sometimes you need to go into settings and turn it on) that will display how many characters you have typed. 

It will be in the format “20/160”. If you go over  160 your phone will automatically add another blank SMS which doubles your character count to 320.

This will happen up to a maximum of 3 times meaning the maximum “single” SMS you can send contains 480 characters. However, it will take 3 SMS messages from your allowance, or charge you for 3 SMS messages.

If you go over 3 SMS (480 characters) your phone “might” auto convert to an MMS format which is because in MMS format, more data can be sent.

Again, on some phones, Samsung in particular, you can turn off the auto MMS conversion function if you don’t want it to happen. You can also set a “warning” that an SMS will be converted – watch for a pop up on screen when this happens.


Adding “Emoticons”


An emoticon is a smiley face, a thumbs up or any other tiny picture that many people like to add to their SMS messages.


Adding an emoticon by itself won’t, in many cases, force the message into MMS format, but, what it will do, is eat up your character count.

A simple smiley face or wink will use 90 characters.

With this in mind it is easy to see how just by adding 3 emoticons actually reduces your character count to only 210 letters (that’s not much!)

You can avoid this by inserting a smiley using keyboard characters rather than hitting the emoticon key and choosing a picture. A smile can be written as : ) or a wink as ; ) 

On some phones you will find 2 versions of emoticons (pretty ones and basic ones).

The basic ones will use less characters but you should always keep your eye on character count and auto MMS conversion.


Group Messages

Another popular way of sending an MMS unintentionally is by sending a group message.

O2 recommends that you send group texts in baches of five recipients to prevent this.


Turning Off

If you are not interested in sending (or receiving) MMS messages at all you can either turn off the option in settings (most phones provide this function) or disable the MMS apn.


Under your phones network settings you will see a section called “access point names” or “apn’s”. You will see either one or two apn’s listed. If you have two, the second one will be the MMS control. If you only have one the MMS control will be down the bottom of the apn settings. Just highlight the apn and choose “edit”.


Look for:

MMSC - http://mmsc.mms.o2.co.uk:8002
MMS Proxy -
MMS Port – 8080


and insert a * or # at the beginning of each line.

This will disable the apn completely but you will be able to easily edit it back again if needed at any time.



Other options are available these days and MMS is old clunky tech that can be avoided.

BBM, Whatsapp, Facebook, Viber email etc are all popular alternatives for sending pictures, video’s and large files that will use your data allowance and therefore will prevent the additional charges generated by an MMS message.


I’ve tried to cover as much as possible in this guide, but as always, I will have missed a scenario, so feel free to add any more tips or instances where you have found an MMS appearing where you were expecting an SMS.

Link to O2 offcial advice here


Video guide by O2

O2 have created a video guide on the subject. 


on ‎21-08-2017 16:28
Many thanks for your reply.
on ‎25-04-2018 21:09
Legend. Thank you
on ‎02-08-2018 12:45

Article is very helpful but my new Galaxy J5 [2017] only shows full keyboard when adding * or # to MMSC & MMS proxy.

Try to edit 8080 MMS port and I only get a limited numeric keyboard with no additional symbols.

Glad for any advice.

‎02-09-2019 18:16 - edited ‎02-09-2019 18:25

One point for iOS... 


If sending to a GREEN bubble recipient – i.e. non-iMessage, vanilla SMS ones: 

YES, the character counter does appear. 


If sending to a BLUE bubble recipient – i.e. iMessage, non-SMS ones: 

NO, the character counter doesn't appear.

(presumably because there are no restrictions on iMessage text amount, and added media can be upto 100MB or 224MB [I've read different amounts online, so unsure true figure]). 


If sending to a mix of Apple/non-Apple users, then the bubble colour will be GREEN – i.e. will send as a vanilla SMS: 

Thus YES, the character counter does appear.* 


* Note: Be careful, as selecting someone's mobile# may mean they are a BLUE bubble, but sending the message by entering their email address in the Messages app will result in it going as a GREEN bubble. 


Mind you, aren't most users (or at least those on mid-to-higher plans) on unlimited SMS anyway. So sending large messages is unlikely to be a problem. 

on ‎02-09-2019 18:41

As long as you have MMS off in settings it will send as SMS and will come from text allowances. 

on ‎07-01-2020 18:24
A key piece of advice for iPhone owners who use iMessage for group messaging, or to send multimedia, eg photos, to other Apple users:

Go to Settings > Messages > and turn off “Send as SMS”. This will ensure your iMessage is always sent as an iMessage, rather than falling back to an SMS or, more crucially, an MMS. (This happens when either you or your recipient has poor or no 3G/4G/5G or WiFi connection.)

Not essential, but I also enable “Low quality image mode” (final option at the bottom of the Messages menu) which compresses photos/videos and therefor speeds up sending and uses less data. Otherwise iMessage sends your images full resolution, which is both a blessing and a curse.
on ‎07-01-2020 18:32

Not correct @graclarkey 

Send as SMS is safe to have on. You need to turn off MMS Messaging to prevent messages from being converted to MMS.

on ‎08-01-2020 15:01
The “Send as SMS” setting only affects the behaviour of an iMessage, of course, although it should really be called “Send as SMS/MMS”, as it prevents an iMessage being converted into both these types of text message.

There are other reasons that I keep “Send as SMS” turned off, including:
- A better iMessage texting experience when dipping in and out of reception, eg, on a train.
- Encryption guaranteed, and certainty about whether or not a message has actually been delivered.
- It eliminates the risk of incurring international texting charges when messaging whilst traveling abroad, or when messaging Apple-using friends with foreign numbers who live in other countries.
on ‎27-01-2020 21:15

I have none of these settings. i want to turn off MM's - i have a LG G5 phone,



on ‎27-01-2020 21:30


Just delete this part of your apn:

MMSC - http://mmsc.mms.o2.co.uk:8002
MMS Proxy -
MMS Port – 8080

on ‎27-01-2020 22:04

That link don't work

on ‎27-01-2020 22:10


It's not a link, it's an address.

Just delete those lines from your apn.

on ‎01-02-2021 15:14

Thanks, a great explanation for why I've been charged for sending a photo attachment (I have PAYG £10 Big Bundle). Just switched from Three PAYG, charge must have been less there because I did it quite often, but it didn't particulary eat up my PAYG like it does on 02.


Will be wary of it now (I've always converted long text MMS down to shorter SMS, or split it up), so now I know to be mindful of the photo's & emoji's on 02.  Easy info & video was great. 


Now I may have to try to find out why, on 02, text MMS seems to take ages to 'go'. Took so long I 'dismissed' the send & rang instead!