Police blamed it on foggy weather and her focus on her GPS.
The 23-year-old woman said she was following the GPS instructions while driving in the dark late Thursday.
She apparently took a wrong turn, drove down a boat launch, and plunged right into little Tub Harbour.
The woman was able to roll down her window, get out and swim to shore. The car, meanwhile completely sank.
A tow truck pulled it out the next morning.
Except for being cold and wet, the woman was not hurt.