Nicole Richie in Sardinia, Italy on July 19, 2013 Credit: CIAO/AKM-GSI

Hottie on board! While vacationing in Sardinia, Italy, Nicole Richie showed off her super-slim bikini body while enjoying a yacht and water activities with her family.

Rocking a teeny red string bikini, the mom of two wore a pair of sunglasses and held her cellphone as her husband, Joel Madden, jet-skied with son Sparrow. 

It's been a fun, beach-y July for the designer and her brood. On July 17, the Fashion Star mentor, 31, also looked stunning in a red and blue colored bikini while enjoying beach time with her Good Charlotte rocker hubby, her 5-year-old daughter Harlow and Sparrow. 

The star, who's been documenting her trip via Instagram, seems to be happy as ever spending quality time with her brood. "Love in Portofino," she captioned one sweet picture of herself with Madden, 34, whom she married two years ago. The family has also been seen in St. Tropez and Corsica.