The pair were spotted returning to Los Angeles from French Polynesia on Sunday after spending a week there.
Dressed comfortably in a loose black top, a gray cardigan and a white patterned scarf, Kunis – with her ever-growing baby bump – hopped off an Air Tahiti flight with her fiancé, who donned his signature white Cubs hat, according to a post on Instagram.
As reported on several social media posts, the couple were spotted by locals on the island of Taha'a and even stopped to sign autographs for fans.
After touching down in L.A., Kutcher, 36, and Kunis, 30, visited her parents' home.
The trip was a much-needed break in the couple's busy preparation for their new life as parents to a daughter. In May, they purchased a private three-bedroom home in Beverly Hills.
"They are looking for more security now that they have a baby on the way," a source close to Kutcher told PEOPLE. "They're in the nesting phase."