Scott Disick -- Miami Heat with 18-Year-Old Rebound Chick (PHOTO)

Scott Disick just took his talents and his relationship with blonde model Lindsay Vrckovnik to South Beach.

They started hanging out in New York this week, but looks like Scott's gonna hang on to her for at least a few more days ... since their all-nighter turned into a weekend getaway.

32-year-old Disick and the 18-year-old model, who just graduated high school (congrats!) were in Miami cruising from the schmancy Setai Hotel to the beach.

We're told Scott was very flirty with his new lady friend, and spent hours on the beach together.

At least he's spending time with a kid ... just not his own.