The 40-year-old actress was photographed in red bikini bottoms and a striped top as she soaked up some sun with friends.
Besides playing villain Miss Hannigan in the remake of Annie, Diaz has kept herself busy promoting her new book, The Body Book.
In her book the Crazy About Mary star discusses the importance of knowing you body and how it works. During a promotional interview with Oprah, Diaz spoke about aging and how women should be able to "learn about yourself and see yourself and start to live with who you are as you go."
"I get so mad when I hear on commercials on television say 'Anti-aging,'" Diaz admitted to Oprah. "We don't honor the journey, and who we are and how much we have to offer. It's almost as if we have failed if we don't remain 25 for the rest of our lives. Oh I'm sorry, I apologize, I wasn't able to defy nature!"