Kourtney Kardashian and Scott Disick are the chummiest exes ever -- so chummy they may not actually be exes!

Kourtney and Scott may have kept quiet on social media about spending Father's Day together -- but we stumbled upon the parents having a late Dad's Day lunch at the Biltmore in Santa Barbara on Sunday. No, really -- we were just having a relaxing Pina Colada on the patio and there they were!

Kourt, who was joined by a nanny, donned a pink slip dress over a white t-shirt (we're pretty sure she stole the look from Nori) and made sure to kick back her feet while she noshed with Scruffy Scott and her three children, Reign, Penelope and Mason.

The two appeared to be getting along swimmingly despite their rocky romance. The LD looked super casual and didn't wasn't stumbling around -- so perhaps he was able to take his party boy ways down a notch for the holiday.

"Kourtney and Scott were definitely acting like a family. There wasn't a hint of problems. These two seemed much more than friendly exes," said our insider on the scene.

None of the other Kardashian gals were on the vacay -- so we can only assume that this was a little romantic jaunt for the two. Maybe they can add a fourth rugrat to the growing brood? We're sure the Lord would just loooooooove that!

After the long lunch, the family all hit up the Santa Barbara Zoo. The kids looked thrilled to have mom and dad together!