The EU is investigating Pornhub, Stripchat and two other pornography websites it believes may be falling foul of its online content laws.
The European Commission said the sites, which also include XVideos and XNXX, did not appear to have measures in place to safeguard children and their rights.
It said this included an apparent lack of “appropriate” age verification methods to stop children accessing adult material.
“Online platforms must ensure that the rights and best interests of children are central to the design and functioning of their services,” it said.
The BBC has approached Pornhub and Stripchat for comment.
The Commission said its initial investigations found the four platforms had not put in place “appropriate and proportionate measures to ensure a high level of privacy, safety and security for minors”.
It said the platforms also do not appear to be abiding by requirements for porn sites to use age verification tools to protect children from accessing adult content.
A Commission official said that “click away” pop-ups currently used by some porn sites, asking users if they are over 18, may not be an effective means of doing so.
The platforms were also found not to have put into place “risk assessment and mitigation measures of any negative effects on the rights of the child, the mental and physical well-being of users,” it said.
It comes amid wider scrutiny of online pornography services worldwide, with many regulators looking to crack down on those that do not have age verification in place.
The UK’s online safety regulator Ofcom recently announced two investigations into porn sites that did not appear to have any methods to check the age of users.
It said in early May that Itai Tech Ltd – which operates a so-called “nudifying” site – and Score Internet Group LLC had failed to detail how they were preventing children from accessing their platforms.
Pornhub is the most visited porn site in the world – and the 19th most visited on the entire web, according to data from Similarweb.
But it finds itself under increasing regulatory pressure.
It has blocked access to its site in 16 US states, including Alabama, Florida, Louisiana and Texas, that passed laws requiring it to verify the age of users.
In a January blog post, it said age verification should take place on users’ devices, such as through their operating system, rather than on individual, age-restricted sites.
It said this would be a simpler process for regulators and enhance privacy for users.
The companies subject to the EU’s investigation were designated as very large online platforms under its Digital Services Act (DSA) in 2023.
Under the bloc’s sweeping set of digital content rules, they face tougher requirements to tackle harmful and illegal material on the platforms.
If suspected infringements of the DSA are confirmed, platforms could face further enforcement actions or, ultimately, a fines of up to 6% of their annual turnover.
The Commission said on Tuesday that Stripchat would no longer be designated a so-called VLOP, but its suspected non-compliance with its digital content rules would still be investigated.
Smaller platforms that do not meet the 45m EU user threshold must also abide by the bloc’s digital rules to safeguard children, it said.
Coordinated action by its member states will also seek to enforce requirements for smaller pornography sites.
“Our priority is to protect minors and allow them to navigate safely online,” said Henna Virkkunen, the Commission’s executive vice-president for tech sovereignty, security and democracy.
“Together with the Digital Service Coordinators in the Member States we are determined to tackle any potential harm to young online users.”
