He claims that the move will protect the site from armies of bots which have plagued X since the beginning.
In a conversation with Israeli Prime Minister Benjamin Netanyahu, the billionaire said a payment system was the only way to counter bots.
"We're moving to having a small monthly payment for use of the system," Musk said.
It is unclear whether this was just an off-the-cuff comment, much like when Musk promised that the world will have affordable robots doing household chores this year, or something real.
Musk has long said that his solution for getting rid of bots and fake accounts on the social media platform is charging for verification. The downside of this is that users will leave the site in droves. The site has suffered since Musk let back a whole basketload of deplorables, neo-nazis, racists, and homophobes back on the site to harrass liberals and scientists who don't believe the world is flat.
The platform has been accused by the Anti-Defamation League (ADL) campaign group of not doing enough to stop antisemitic content. In a statement, the organisation said that Mr Musk was "engaging with and elevating" antisemites.
Since taking over Twitter last year he has looked to incentivise users to pay for an enhanced service, which is now called X Premium.
This has been done by giving paid subscribers more features, like longer posts and increased visibility on the platform.
X Premium currently costs $8 (£6.50) a month in the US. The price differs depending on the subscriber's country.
Mr Musk's conversation with the Israeli prime minister also touched on antisemitism on X.
Earlier this month, he said that the company would sue the ADL to "clear our platform's name".