Kim and Kourtney Kardashian put on a sizzling display as they rock matching black bikinis

Kim Kardashian celebrated National Siblings Day by posting a photo of her with her older sister Kourtney on their recent vacation to Turks and Caicos.

Kim Kardashian, 37, has been posting numerous photos of her in different swim attires during her recent beach vacation with Kourtney, 38.

In the most recent photo, the two could be seen laying down on a beach bed, staring at the camera. Kourtney donned a green high-waisted bikini and sheer cover up, while Kim sported a black bikini bottom and camoflauge top. The two sisters had on mini-sunglasses to shield their eyes from the sun.

While the Kardashian duo seemed to be having a lot of fun, their other sister Khloe, 33, has been stuck in Cleveland, Ohio, getting ready for the birth of her first child.

Both Kim and Kourtney have been sharing a lot of daring photos from their quick bonding time together, and based on what the two of them have been sharing, they are both in their best shape.

From photos surfing, to laying out in the sun, these brunette beauties are definitely fit.

These photos posted by the two siblings come before news broke out that their youngest Kardashian sister Khloe was caught being cheated on by her boyfriend and baby daddy Tristan Thompson.

Video footage of Thompson kissing other girls in FOUR different occasions spread on the internet like wildfire just this week.

Representatives from both Thompson and Kardashian have not spoken about the issue.