Hundreds of thousands of Australians under 16 will be kicked off their accounts and blocked from making new ones on Wednesday.
Facebook, Instagram, Threads, TikTok, Snapchat, Twitch, Kick, X, YouTube and Reddit are be among those to be banned, with fines of almost $50 million for failing to take action in removing under-16s from their platforms.
Communications Minister Anika Wells has said the list of sites is dynamic and may expand if children migrate to other platforms not already included in the ban.
Bluesky, which functions similar to X, announced on Tuesday it will comply with the laws despite not being on the eSafety Commission's list of banned platforms.
The laws are supposed to apply to all social media sites.
"We've upgraded our age assurance system to comply with upcoming laws in Australia and other regions," Bluesky said in a statement.Â
It comes as popular online forum Reddit, which was added to the list in early November, indicated it may launch legal action against the "erroneous" ban.
Reddit enlisted barrister Perry Herzfeld SC to mount a legal challenge, supported by law firm Thomson Geer, the Australian Financial Review reported.
A spokesperson for the San Francisco-based platform did not deny the company was preparing a lawsuit.
"The only decision we've made is to comply with the law," they said.
In a post to users, Reddit spelled out how it would comply with the ban despite disagreeing with its scope, effectiveness and privacy implications.
"By limiting account eligibility and putting identity tests on internet usage, this law undermines everyone's right to both free expression and privacy, as well as account-specific protections," the post read.
The post said the laws go "far beyond the intent of the Australian parliament, especially when other obvious platforms are exempt".
Under changes on the platform, new Australian users will provide their birthdate during sign up and all account holders will be subject to an "age prediction model".
If they are believed to belong to a user under 16, accounts will be suspended, but there will be an opportunity for users to appeal and verify their ages.
Ballarat schoolgirl Pippa Martin, 13, was feeling positive about getting her attention back as she snuck final scrolls of her social media accounts before the ban comes into effect.
"Sometimes I see videos of someone else playing the piano and I think I'm never going to be that good and I should just stop trying," she told AAP.
"I feel like now I'll start playing the piano more without my apps."
The social media age limit is attempting to protect children from online harms and what Ms Wells has described as "predatory algorithms".
Pippa said she had previously been exposed to harmful content, including a video of American political activist Charlie Kirk being fatally shot in September.
She hoped to feel more present with her friends and thinks the ban will help prevent "toxic" fears of missing out on events that she sees her peers post about.
Lizzie Muller, the mother of a 14-year-old girl, doesn't believe the ban will work how the government wants it to but was pleased it has started conversations about online harms.
"When your kids' world becomes more and more mediated by social media, it becomes harder as a parent to hold that line," the Wollongong woman said.
"It's kind of useful for the ban to be a talking point."
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