Steve Jobs' widow brought her best accessories to Croatia -- her daughter, hot bf and Steve's yacht.

Laurene Powell hit up the historic city of Dubrovnik in southern Croatia flanked by 19-year-old daughter Eve and bf Adrian Fenty ... the former mayor of D.C.

Docked not far off the coast was the 256-foot, $100 mil yacht, Venus ... commissioned by the late Apple founder back in 2008. He never got to enjoy it -- Steve died a year before it was finished in 2012.

Laurene will take it from here ...