The L.A. Clippers superstar was down in Mexico this week hitting the town with his GF, Kishele Shipley ... and locals tell us the Finals MVP was cool as hell.

But, most importantly, they noticed his dope tank ... which featured one of his famous slogans, "Don't be mad" -- as well as his own jersey number AND name!

Yeah, pretty baller move.

We're told Kawhi was enjoying the Mexico sun ... and he even appeared to get in a little boating while in town!!

Of course ... Kawhi is no stranger to a good time on off weeks -- remember, the NBA star hit a floaty boat on the open seas near Barbados back in June after his Raptors championship.

But, it's back to reality this weekend for the 28-year-old ... the Clips play the Kings on Saturday afternoon at Staples.