Kylie & Kendall Jenner's Bootyful Celebration

Kylie and Kendall Jenner paraded around Turks and Caicos in skimpy bikinis ... not that we're complaining.

Kylie celebrated her 19th birthday on the island and brought along her sister and some friends. Check out the pics ... oughta get you ready for thirsty Thursday.

Oh look ... there's Tyga!