Kourt & Ky swim session

A photo posted by King Kylie (@kyliejenner) on



Kylie Jenner's about to be jailbait no more!

The soon-to-be 18-year-old posted yet another insanely sexy bikini selfie -- because obviously she values what's on the inside.

The 17-year-old showed off her figure in a skimpy black two piece, which she accessorized with gold bangles.

Kylie and recently single sister Kourtney Kardashian decided to take a break from their exhausting life of primping and posing to take a swim on Sunday. The teen captioned the photo, "Kourt & Ky swim session" -- because she's a clever and brilliant mind.

The youngest Jenner turns 18 next Monday and will be toasting being legally able to sleep with her 25-year-old boyfriend by holding a big bash in Montreal, Canada next weekend. We wonder if she will taking advantage of the Canada's drinking age? We think so!