While anybody could join the original website, content filters and human moderators were employed to stop inappropriate messages or personal information being shared.
But Disney closed the website in 2017.
Since then, unofficial clones of the website have been set up. These so-called 'private servers' were launched using stolen or copied source code, and can easily be found by children searching the internet.
Club Penguin Online was the largest of the unauthorised clones and the subject of a BBC investigation in May 2020.
Its popularity exploded during the coronavirus pandemic, with seven million registered players.
The BBC investigation found racist, homophobic, anti-Semitic and sexual messages flowing freely on the unauthorised platform, which saw children playing alongside adults.
Disney said it was "appalled" by the website and ordered it to close or face legal action.
But many players simply moved to another major site, Club Penguin Rewritten, which - nearly two years on - has now been closed.
The site included in-game advertising, although it is not known how much money was generated.
One player, who spent time on both sites, told the BBC: "The game had been booming ever since Club Penguin Online's [CPO] shutdown, as that is where the CPO player population migrated to. However, that may have worked against them in the end."