In a parade of barely-there swimsuits and bikinis, the women showed off the results of their hard work in the gym.
Kim’s trainer, Melissa Alcantara, was even along for the trip.
Since enlisting body builder Alcantara’s help in September 2017, Kim has been open about how incorporating weights into her workouts has helped tone her muscles and define her famous frame.
“I was almost 140lb [63.5kg] forever and now I’m like 116lb [53kg],” she told WHO in August last year.
“It just feels so good. I didn’t see results right away, but when you stick with something and you’re consistent, you will,” she added. “I love it.”
That consistency translates to 90-minute, 6am strength training workouts six days a week with exercises focusing on toning specific body parts: shoulders, biceps/triceps, and chest/back, as well as three days devoted to legs.
They also do cardio exercises –either short bursts of high intensity or more prolonged, low-intensity walks.
Overhauling her eating meant reducing sugar, steering clear of processed foods and sticking to lean meats, fruits, vegetables, healthy fats and carbs from sources such as oats or whole grains.
“When we met, Kim told me she’s tired of doing little diets,” Alcantara has told WHO.
“She didn’t want to be skinny. She wanted to have muscle and feel strong. And she wanted to find something she can do for the rest of her life.”
Likewise, Kourtney, 40, has made healthy eating part of her lifestyle, crediting avocado, wholegrain porridge, collagen smoothies and apple cider vinegar for her fit frame.
Still, in a recent post to Poosh, her health-and-wellness focused website, she shared how she sometimes strays from her organic and keto diet.
“I cheat twice a day with a little something sweet after lunch and dinner,” she said in the post.
“Indulging every once in a while is self-care.”
Her fitness routine, too, is part of her self-care.
“I take time for myself to work out every day, which I never did – especially having three young kids,” she has told E! “I just never made it a priority, and now it makes me feel so much better – mentally and physically.”
The celeb sister also observes a strict low carb diet and workout routine, and there's no doubt that it has paid off.
Reality star sisters Kim Kardashian West and Kourtney Kardashian took their kids to Costa Rica fora tropical getaway filled with sun, sand and selfies.
A source tells WHO that Kim, 38, and husband Kanye West, 42, left 6-week-old son Psalm at home, but brought along their three oldest kids — North, 6, Saint, 3, and Chicago, 1 — while Kourtney travelled with ex Scott Disick, 36, and their three children, Mason, 9, Penelope, who turns 7 on July 8, and Reign, 4.
“They are all filming for the show [Keeping Up with the Kardashians],”the source says.
“They have a lot of ocean and rainforest activities planned.”
For the full interview pick up the latest issue of Who!