The model, 21, and the reality TV star, 38, looked more like twins in their thigh-high, one-piece swimsuits.
Kourt posed more like a Baywatch star in her red suit while Kendall dared to be different in plunging back, animal-printed one.
The mom-of-three was spotted with her new man, Younes Bendjima, in the French town. They showed off their love with lots of PDA!
Meanwhile, Kendall has been rubbing elbows with fellow model bestie Bella Hadid and fashion icon Naomi Campbell.
Kourt has been seeing the Algerian model off-and-on since December 2016 though they are rarely spotted together.
What do you think about Kendall and Kourtney's hot bikini bodies?