Dirk Nowitzki's done playing ... but his body sure as hell didn't get the memo ... 'cause the recently retired NBA superstar ditched his shirt on vacation in Mexico -- and the dude looks jacked!!!
The Dallas Mavericks legend and his wife, Jessica Olsson, hit up the beach in Tulum earlier this week ... makin' a splash and enjoying every bit of the unemployment life.
Dirk's got a LOT to celebrate -- he finished his career as the 16th top scorer to ever play in the league ... and the Mavs' all-time leader in points, rebounds, blocks and games played.