Trolls have been disrupting video conferences with offensive content, including racist and homophobic imagery.
Those with free Zoom accounts must use a password for all meetings.
It follows reports that a sexual assault awareness meeting on the platform was targeted by a hacker who posted a video depicting child abuse.
Zoom has been attempting to toughen up its security measures ever since it vowed to fix its "biggest trust, safety and privacy" issues in April.
Its latest move, aimed at free users of its platform, will be implemented on 9 May.