Almost 20% of children are talking to strangers online every day.
The annual report for CyberSafeIreland found 20% of 12-year-olds are spending four hours or more online daily, and 18% of 8 to 13-year-old children are talking to strangers every day, which is a three-fold increase from last year.
The revelation comes as the Government and social media companies are urged to take stronger action to protect young people online.
Age restrictions on popular social media sites are meaningless according to new research which shows 68% of 8 to 13-year-olds own their own smartphone with a similar number using social media and messaging apps.
A survey of over 5,000 children, parents and teachers found that 41% of 8 and 9-year-olds are playing games for over-18s, which can expose them to inappropriate and potentially damaging content.
CyberSafeIreland says the data highlights the need for education programmes with parents and children, adding that it is vital the Government does more to address the issue.
Alex Cooney, CEO for CyberSafeIreland, said: “There has been a significant spotlight in the media this year on the Digital Age of Consent and lots of debate around what age is the 'right age' for children to start using technology more independently.
"The data we have gathered shows that 9-year-olds are likely to own a smartphone and be on social media, despite age restrictions and despite the Digital Age of Consent being recently set at 16. Our data highlights the need to start education programmes with both parents and children from a young age with a focus on children embracing a more positive use of technology.
"It’s vital that the Government does more to address this issue and goes further than its recent Action Plan on Online Safety to set clear time-bound targets by which the success of its policies can be measured," he said.
Cliona Curley, CyberSafeIreland’s Programme Director and cybercrime investigation specialist, said: “The reality is that we are not addressing online safety with our children either at home or in school early enough.
"We need to teach children digital literacy skills so that they are able to critically assess information and make smart choices online. We urgently need to make the online safety of our children a national priority," she said.