About 3:30 p.m. near Seascape Boulevard and Sumner Avenue, a man who drove a black, 2006 to 2008 Toyota sedan approached two 16-year-old girls, said deputy April Skalland.
He opened a car door and masturbated, authorities said.
The suspect was described as a stocky white man in his 20s or 30s with light-colored hair and a beard, authorities said.
About 3 p.m. Saturday, a man with a similar car drove up to a group of women and girls on Airport Boulevard near Oliveira Loop in Watsonville. He also started masturbating, Watsonville police said.
Authorities are investigating to whether the cases were related.
The Santa Cruz County Sheriff's Office asks anyone with information to call 471-1121. Watsonville police ask anyone with information to call investigations at 768-3350 or leave an anonymous tip on the tip line at 768-3544.