Stella Hudgens Parades Curves in Busty Blue Bikini

Step aside Vanessa Hudgens ... 'cuz your lil' sis is bursting through with her bikini bod, and these hot shots are ones for the books!

The 29-year-old actress hit the balcony during sunset hour -- rockin' this itsy-bitsy blue bikini for a 'shoot -- and the Instagram likes are piling in!