More than half of parents in the East Midlands are not aware of the age limits for social media sites, according to research by the NSPCC.
The children's charity is now calling on social media companies to make the age restrictions clearer on sign-up pages, and is also offering advice to families to help keep children safe online.
Of the East Midlands parents surveyed by the NSPCC, more than one in five thought there were no age requirements for social media sites like Facebook.
Social media can provide important support networks for young people. But the sites can also be a dangerous place for younger children, potentially exposing them to bullying, inappropriate content or grooming, the charity says.
Calls to the NSPCC’s Childline service calls show that children under the age of 13 are using social networks and are in some cases having negative experiences online.
Ally Sultana, the NSPCC’s Midlands Campaigns Manager, said: “We can all do our bit to keep children safe online, and ensure their experience of social media is a positive one.
“Age restrictions need to reflect the content and conduct possible on each site and be crystal clear to parents and their younger users. And platforms need to work harder to protect children and young people, building in child safety to the design of each site.
“Parents can be proactive by having conversations with their children about online safety as soon as they start using the internet. The NSPCC’s Net Aware service can give practical tips such as how to switch on parental controls, or manage privacy settings.”
The Net Aware website, run in partnership with O2, offers parents useful information about each social network, including the age guidance for users. The service, at www.net-aware.org.uk, works with over 500 parents and carers, and 1,725 young people to review social networks, apps and games that children use.