The ICO said the fine had been levied over “failures” falling between 5 May 2018 to 8 July 2025, when it said Reddit was processing the personal information of children under the age of 13 unlawfully.

The regulator said companies operating online services likely to be accessed by children had a responsibility to protect them, including by making sure the way their data was collected and used did not expose them to risks.

“To do this, they need to be confident they know the age of their users and have appropriate, effective age assurance measures in place,” said Edwards.

“Reddit failed to meet these expectations.”

On 8 July 2025, Reddit started verifying the age of users in order to comply with the requirements of the Online Safety Act (OSA).

But the ICO said the platform relied on asking users to declare their age when opening an account – a technique it said was “easy to bypass” – so said it would continue to monitor the situation.