Multiple 911 callers reported the shooting about 1:25 p.m. in the area of Blaisdell Way and Nichols Avenue, police said.
The victim was pronounced dead at the scene.
INTERACTIVE: Take a look at the ABC7 Neighborhood Safety Tracker
Investigators, in a press release about 6:45 p.m., asked people to stay out of the area for the next several hours.
Police said updates would be provided as more information becomes available.
Anyone with information is asked to contact the Fremont Police Department Investigations Unit at (510) 790-6900 or text "Tip FremontPD" to 888-777.