The actress looked happy as she enjoyed some quality family time. Taking turns with Cash to play with the children, she was spotted twirling Haven, two, through the air and playing with Honor, five, in the sea.
The mum, 32, wore a purple two-piece that showed off her slender physique. A floral cover-up and a wide-brimmed straw hat made sure she had some protection from the sun.
Jessica was also spotted chatting to friends as they frolicked on the beach. Samantha Ronson was also at the party, and she posted a sweet picture of Jessica and her girls eating lunch while they were there.
"This gang! @jessica alba," she captioned the snap.
It's been a busy summer for the family. Jessica and Cash celebrated their fifth wedding anniversary in May and in June, Jessica threw a birthday party for Honor at their Beverly Hills home.
She also attended a Beyoncé concert in July and took Cash to see Justin Timberlake and Jay Z's show at the Rose Bowl.
Jessica recently reprised her role as Special Agent Sartana Rivera in upcoming Robert Rodriguez film Machete Kills.
The film is a sequel to Machete and will also feature appearances from Lady Gaga, Sofia Vergara, Vanessa Hudgens, Mel Gibson and Charlie Sheen.
Jessica has also reprised her role as Nancy Callahan in Sin City: A Dame to Kill For – the movie that put the actress on the map.
She won international recognition as the stripper in 2005 release Sin City.