Jenner is vacationing in Mexico with boyfriend Tyga, 25, and some of her close girlfriends after turning 18 on Monday.
The young reality star was photographed riding a Jet Ski with the rapper Tuesday and also posted Instagrams on Thursday of the group's fun in the sun.
Jenner styled her ever-changing hair in black and blonde cornrows.
Before arriving in Mexico, she posted a photo of her new Ferrari (given to her by Tyga) alongside the jet on her Instagram, captioning the photo "GONE."
Despite her birthday bash last Sunday and her current vacation, Jenner isn't done celebrating just yet. The party continues into the weekend with the Keeping Up With the Kardashians star's scheduled club appearance in Canada on Sunday.