Google, Meta and TikTok have filed separate lawsuits against California, seeking to block a new law aimed at protecting children from harmful social media features, arguing that it violates their constitutional right to freedom of expression.

The legislation, signed by Governor Gavin Newsom in September, is scheduled to take effect on 1 Jan 2027. It prohibits technology companies from providing users under 16 with potentially addictive features, including personalised feeds, endless scrolling and automatically playing videos.

The law also requires companies to take “reasonable measures” to verify users’ ages and prevent children under 16 from accessing these features.

The three companies filed separate lawsuits in federal courts in San Francisco, Los Angeles and San Jose.

Besides challenging the law under the First Amendment, they argue that it violates Section 230 of the 1996 Communications Decency Act, which generally protects technology platforms from legal liability for content posted by third parties.

The legal challenges come amid growing scrutiny of social media companies over the impact of their platforms on children’s well-being. Schools, government authorities and individual plaintiffs have filed thousands of lawsuits alleging harm to young users.

In August, Meta agreed to pay up to $18 billion and introduce stronger child-safety measures on Facebook and Instagram under a landmark legal settlement.

The agreement ended a trial concerning teenage social media addiction and resolved claims brought by nearly every US state over the platforms’ alleged role in harming children’s mental health.

The legal action focused on platform features designed to keep young users engaged for extended periods.

In September, TikTok also reached a settlement with Alabama over allegations involving addictive features.

California Attorney General Rob Bonta’s office, which is representing the state in all three cases, said Thursday that it was reviewing the lawsuits and remained committed to defending legislation designed to protect children online.

TikTok described the California law as an unconstitutional restriction on free expression, arguing that it undermines the established practice of recommending and organising content according to users’ preferences, a system also used by bookstores, television networks and streaming services.

The company said it had introduced several safety measures for younger users and argued that the legislation disregards progress in online child protection, restricts free speech and undermines parents’ authority to decide what content is appropriate for their children.

Meta argued that the legislation violates the First Amendment by allowing the government to determine how information and ideas are organised, displayed and shared with California residents.

The company said it would be forced either to remove features that help maintain age-appropriate experiences for teenagers or prevent thousands of young users in California from connecting with family members, friends and their communities.

Google said parents were best placed to make decisions for their children and highlighted the parental controls and safety protections already available through its services.

“Overly broad laws like this actually break the systems we’ve built to help kids find high-quality, age-appropriate videos,” Google spokesman José Castañeda said.