Rihanna's back at it, rocking everyone's world as she left the downtown L.A. courthouse where her man A$AP Rocky is going through his criminal trial.

The singer kept the style parade going, wearing a trench coat as she was filmed leaving the courthouse with a bodyguard Thursday ... her fourth time supporting her partner at trial.

Of course, her presence isn't low-key -- it's RiRi, so the media hoopla was inevitable. She knew it was coming, so she flew under the radar on day one, slipping into the courthouse undetected, but since then, she’s had to enter and exit through the regular areas.

Once inside, things have been chill -- she’s been seen sitting with his family, including his mom and sister, as the trial’s been moving forward.

A$AP Rocky’s on trial for allegedly shooting his former friend A$AP Relli during a heated 2021 showdown in Hollywood.

The D.A. slapped Rocky with two felony assault charges after his 2022 arrest at LAX ... only moments after the plane he was flying on with Rihanna touched down from their trip to Barbados.

If convicted, Rocky’s looking at up to 24 years in prison ...  but he's seemed pretty confident so far, turning down a plea deal.