Also present was Simon's ex-girlfriend, Terri Seymour, her boyfriend, Clark Mallon, and their daughter Coco.
The Britain's Got Talent judge dated Terri from 2002 to 2008, and the former couple have remained on good terms since their split.
WATCH: Simon Cowell enjoys birthday celebrations with son Eric
Terri shared a series of snaps of the friends all together, as well as the children sat at the table near a luxurious home pool.
A small clip showed the three youngsters on an Easter egg hunt, with Eric and Coco sticking very close together.
"Easter love," Terri wrote to accompany the snaps. "Hope everyone had a safe and hoppy Easter!"
In the group shot, Simon was sitting in a dressing gown with the sleeves rolled up, while beaming at his son Eric.
The friends celebrated Easter in California
The X Factor judge's girlfriend had her arms draped over his shoulders, while her first son stood to her right. To the left of them was Terri, with her arm around the shoulder of Coco, and Clark stood to their side.
Simon was the only one of the adults who wasn't wearing some form of floral print clothing, while the children opted for much simpler outfits.
The Easter photos triggered a huge fan response, with one joking: "It's amazing how they all get along!!"
Simon and Lauren welcomed Eric in 2014
Another added: "Beautiful picture & that view!! I need to get to California!!"
Simon and Lauren welcomed son Eric on Valentine's Day in 2014, and the star recently revealed that his son came up with an incredible nickname for him following his bike accident last summer.
Simon explained to Entertainment Tonight that when he arrived home following the incident, he was feeling incredibly "embarrassed".
The star spent six hours having extensive surgery to fix his back after falling from his electric bike in his Malibu home courtyard. The surgery left him with metal rods and screws in his back.
Simon explained: "He went 'Dad, you look like Iron Man.' And I went 'Yeah, I'm like Iron Man, yeah.'"
Like this story? Sign up to our newsletter to get other stories like this delivered straight to your inbox.