Diddy is already facing off with prosecutors in his sex trafficking trial that kicked off Monday in an NYC courtroom … but he may also have to stare down several accusers who have filed civil lawsuits against him, TMZ has learned.

Florida-based attorney Ariel Mitchell — who represents 3 of Diddy’s alleged victims in civil cases and potentially a fourth — says she might fly up to the Big Apple to attend the music mogul’s federal criminal trial … with her clients.

As you know, Diddy is on trial for allegedly committing a slew of crimes, including racketeering, sex trafficking and transportation to engage in prostitution. He’s also accused of forcing women to engage in “Freak Offs” … marathon sex sessions that include male sex workers, according to federal prosecutors.

She adds, “We are looking into logistics to ensure whoever wants to attend may be afforded the opportunity to see their abuser be brought to justice.”

Day one of the Diddy trial kicked off Monday morning with jury selection … one of the potential jurors — Juror 2 — stood out from the rest, revealing he’s a massage therapist who’s worked in 2 fancy Manhattan hotels cited in a jury questionnaire, and who mentioned recognizing the actors Michael B. Jordan and Mike Myers.

The man also said his sister was a victim of domestic violence, but says he can still be fair to Diddy, who was caught on video beating up his ex, Cassie. That video will be a key piece of evidence in the trial.

Speaking of Diddy, he was dressed in a suit and sporting reading glasses as he sat at the defense table quietly listening to the proceedings … with a full head of gray hair.