Play video content EXCLUSIVE 7/19/18 TMZSports.com

49ers QB Jimmy Garoppolo definitely appreciates a woman with experience ... because he went on a dinner date Wednesday night -- with one of the biggest porn stars in the world!!!

26-year-old Jimmy G and Kiara Mia hit up Avra restaurant in Beverly Hills ... where they walked in arm-in-arm and toasted with wine together at the dinner table.

At the end of the date, the two walked to a waiting car together -- Jimmy had a big smile on his face ... and Kiara's IG account might explain why.

You might be familiar with Kiara's work -- she starred in a "Keeping Up with the Kardashians" porn spoof back in 2015.

She's also graced the covers of classics like "Cougars Gone Wild 2" and "Bra Busters 4."