Joined by some of Holmes's family, the actress, 34, and Cruise, 7, soaked up the sunny, 90 degree weather on Sunday, taking a break from the beach to have lunch at Summer Kitchen Cafe.
"Everyone looked like they were having a great time," a staffer tells PEOPLE. "Katie had a chicken salad and the table was drinking iced tea. There was a lot of laughing. Suri was really polite and so well behaved."
The source adds that the entire table was decked out in "beach attire" with Holmes wearing "a one-piece pantsuit cover-up."
Despite the bustling restaurant, most patrons "left Katie alone and respected her privacy."
Later that day, Holmes stepped out (without her daughter) for a little shopping with a friend in Seaside. The duo stopped inside Duckies Shop of Fun but left without buying anything.
"She just walked around looking," an employee says. "She wore her hair up and no makeup. She was just casual and relaxed."
Holmes stopped into several more shops, including Willow + Woods, a boutique for men and women.
Says one staffer there, "She was really quiet. We barely knew it was her."
– Sara Hammel