The Peruvian joins the League One club until January 2021, which will mark his first taste of senior football in England.
Since arriving from Deportivo Municipal in October 2020 for £210,000, the 22-year-old has spent the early stages of his Magpies career in the under-23s.
Vilca was due to go out on loan in January but an injury delayed his development.
The 22-year-old: “I’m really excited to come to Doncaster and have a chance to show what I can do in England.
“I feel since joining Newcastle I have improved a lot already so this is the next step for me.
“I have heard a lot of positive things about the club and the players here and I am looking forward to meeting my team mates.”
Doncaster, managed by Richie Wellens, are currently bottom of League One, collecting just one point from their opening five matches.
We’ve gathered the best of today’s Premier League speculation below…