Karan, who recently got separated from second wife Jennifer Winget, will turn 33 on February 23. He made his Bollywood debut this year with Bipasha starrer 'Alone'.
The actress posted a series of pictures on her Instagram account from their road journey to the Indian beach state.
Bipasha's close friends -- designer Rocky S, fitness expert Deane Pandey and model Candice Pinto -- are accompanying the duo.
"Goaaaaaaaa!!! Long Drive!! Monkey birthday party begins (sic)," the 36-year-old actress captioned the photographs.
Karan was earlier married to actress Shraddha Nigam and then dated choreographer Nicole Alvares, before tying the knot with Jennifer.