Kendall Jenner was having some fun in the sun with her favorite Sun on Tuesday ... cruising on a yacht with her BF, Devin Booker, in Italy -- and the pics are piccante!!
As we previously reported, KJ and the Phoenix Suns star hopped on a private jet and flew to their romantic getaway last week ... and they've been spending the majority of their time lounging around in some barely-there swimwear ever since.
When we saw Kendall and Devin on Friday, they were floating around in Sardinia .