Update: 4 September 2014: Since publishing this news story on 3 September, Facebook has today confirmed that videos autoplay by default on both the mobile app and on the desktop (we explain how to turn this off on your mobile and desktop below).

Facebook adds that updates to the app will not affect existing settings. So if you turn the autoplay feature off, it will remain off after an update.  

If you use Facebook on your mobile or tablet and you've experienced higher than usual bills, you should check your settings now as it could be due to the social network's autoplay video function.

Facebook has confirmed that videos uploaded onto the site will play automatically in users' news feed by default, both on wifi and on 3G and 4G internet connections, unless you actively opt for it not to.

The social networking site wouldn't confirm whether this autoplay was via the app or on a browser, but when MoneySavingExpert.com asked members of our office to test it, videos appeared to autoplay via the app only.

We've seen many complaints from people who have been stung with data bills after exceeding their monthly allowance and who believe it to be because of Facebook autoplaying videos (see our Cheap Mobile Broadband and wifi guide for cheap 3G and 4G access).

So we're urging those who use Facebook on their mobiles or tablets to change their settings now to either turn off the auto-play feature, or to set it so videos only auto-play on wifi, to avoid being hit with unexpected data charges. We explain how to do this below.

It's even more pertinent that people check now, as an ice bucket charity challenge is flooding many of the social network users' news feeds. The BBC this week reported that there have been in excess of 2.4 million ice bucket-related videos posted on Facebook, and 28 million people have uploaded, commented on or 'liked' ice bucket-related posts.

Facebook's auto-play videos were first trialled in September 2013 – though it wouldn't tell us when the initiative was fully rolled out.

'Catching users out'

MoneySavingExpert.com consumer and features editor Steve Nowottny says: "It's worrying that Facebook is autoplaying videos by default, as it's clearly catching users out, with some claiming they've unknowingly exceeded their data limit and incurred extra charges as a result.

"Anyone who uses Facebook on their mobile or tablet when they’re out and about or using 3G or 4G should check their settings now – change your auto-play settings to off, or so that videos only play over wifi."

'I went over my limit for the first time'

MoneySavingExpert.com asked its Facebook users if they'd reached their data limit faster than normal and whether they thought it was because of the autoplay feature. Many responded to say they had noticed their data usage and bills had rocketed.

Here are some of the comments:

  • Caroline Greenhalgh Baxter says: "I went over my data limit for the first time in May, I turned off Facebook videos and haven't been anywhere near my limit since."
  • Melanie Gillett says: "I went over [my data limit] for the first time in May, but saw a post advising how to change the settings and have had no problem since."
  • Denise Popplewell says: "Using way more data. I turn it off now."

We also tested out Facebook's autoplay in the office on a number of different mobile phones and found the following:

  • Those who logged into the Facebook app using a 3G or 4G connection saw videos on their news feed play automatically.
  • Those using their internet browser to log into Facebook didn't see the videos automatically play.
  • When videos auto-play, the sound is automatically muted unless you click on the video clip.

How do I turn off the auto-play video feature?

  • Apple: Go to your phone's Settings > click Facebook > click Settings > Select 'Auto-play only on Wi-fi', or 'Off'.

  • Android: Android told us Facebook app functions can be controlled through the handset and through the Facebook app itself. When we tried it on a few devices in the MoneySavingExpert.com office, we found the following steps worked via the Facebook app itself: Go to your Facebook account Settings > click App Settings > then within General Settings select 'Auto-play only on Wifi', or 'Off.'

  • Desktop: Go to your computer's Settings > click Videos > click Auto-play videos > click Off.

Unfair charges, who do I complain to?

If you've been hit with charges you deem to be unfair, contact your mobile provider explaining why these are unfair and ask it to refund the money.

If this doesn't work, you can take your complaint to the Communications and Internet Services Adjudication Scheme (CISAS) or to the Ombudsman Services – which one depends on who your provider is signed up to.

What does Facebook say?

We asked for Facebook to provide a response. It confirmed videos do automatically play on 3G and 4G but declined to expand on whether this referred to the browser or to the app, and it refused to comment any further on the issue.