LiAngelo & LaMelo Ball: 1st Lithuania Hoops Sesh ... with LaVar!

The Ball fam is officially ballin' out in Lithuania.

A day after getting MOBBED by photogs at the airport ... LiAngelo and LaMelo are tearin' it up at a private hoops sesh on BC Vytautas' home court -- with LaVar on commentary!!

Gelo's throwin' down 1-handed hammers, Melo's making it rain from deep ... and dad's hyping 'em up like the dude from the AND1 mixtapes.

If you're wondering where their teammates are -- this doesn't look like an official practice ... just the guys gettin' in some extra work.

Bonus: the Big Baller’s already trying to speak Lithuanian! Trying to ...