“Storms comin,” she captioned the picture of herself in a black-and-white bikini, waist-deep in the water and looking out onto the horizon.
The 19-year-old also shared a picture of herself from behind, showing off her long blonde locks and burgundy-colored bikini bottoms.
“It’s all about the angles,” she wrote.
As for how she stays in shape? The star previously told PEOPLE her typical daily diet consists of a nutrition shake for breakfast, a steak or burger for lunch, and chicken and vegetables for dinner.
“Every day I have to have a cheeseburger or chicken tenders at some point throughout my day, and if I don’t have a little something sweet — whether it’s a peanut butter cup, a small brownie or anything chocolate — after dinner, I don’t feel like I ate,” she said. “My mom tries to force me to eat salads, but I’m not a fan!”
Don’t Be Tardy star Kim, 38, was on a romantic getaway on the island with her husband Kroy Biermann last week when four of their six kids — Brielle, Ariana, 15, KJ, 5, and twins Kaia and Kash, 4 — flew over to surprise them for the last couple of days of the trip.
And like daughter, like mother: Kim also took to Instagram to show off her own bikini bod on Monday, explaining that she stays in shape by running three miles five times a week and stays away from red meat.
“It’s genetics OBVIOUSLY,” she wrote. “I never sit down. From the time I get up til the time I go bed. If you think it will make you ‘fat’ it will! MODERATION!! Everything in Moderation. No I don’t do weights I need tooooo but, I went through the windshield of my car at 18 and I have a terrible neck. So I’m working on simple easy exercises. I tend to strain my neck when I do any weights. Everyday is a new day.”
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Over the weekend, Kim took to Instagram and Snapchat to document the family fun — and even a little oceanfront drama that unfolded after a fellow beachgoer asked her kids to be quiet.
“This lady on the beach came up to me and said: ‘Could you keep you and your kids quiet? It’s a very quiet peaceful beach,” Kim recounted on Snapchat. “Bitch, what? They’re 4 and 5. We’ve been nothing but respectful. I told her: ‘Well, why are you always sitting next to me? Move your f—ing chair to the other end of the beach!’ ”
“Until next time!! Turks n Caicos,” she continued on Instagram. “Thankful so incredibly thankful. And to the lady that said to keep it down she would like it to remain quiet on the beach… kiss it where the sun is shining, ‘And loosen up and live a little.’ “