But of course Jenner couldn’t ring in the big 1-9 without a member of her famous family. Kendall seems to have joined her little sister on the tropical getaway, posing for a pic Kylie captioned, "19 & 20."
But being the social media maven that she is, Jenner's birthday wouldn’t be complete without a little Snapchat.
"Happy & having fun. All I could ask for on my bday," she posted while catching some sun.
"I can't believe I'm 19!!! When I look back at the past year and all that has happened, it's seriously crazy," she wrote. "I can't even imagine what this next year will bring -- not only for me, but for my friends and family, too!"