Kim Kardashian Rocks a Black Thong Bikini on Instagram

Kim Kardashian was seen in a black string bikini while on a white sand beach in two new Instagram photos shared on Monday.

The mother-of-four was in top shape as she was photographed from the front and the back as the crystal blue waters could be seen behind her.

The makeup mogul, 40, had a bit of fun with her caption as she wrote: 'Resting beach face.'