The girls had a blast as they hung out in the jacuzzi, splashed around on the beach and enjoyed some great Mexican cuisine.
The former Simple Life star and mother of two took a few days off to relax with with her pal celeb DJ and former Lindsay Lohan-girlfriend Sam Ronson.
Nicole was also spotted having a lunch with Jessica Simpson and her sister Ashlee, who had her new boyfriend, Boardwalk Empire star Vincent Piazza, in tow.
Looks like the ladies had a spectacular time soaking up the Mexican sun. Happy Birthday Nicole!