The 49ers unveiled their new threads to the public in April.
Under NFL rules, teams are allowed to wear an alternate uniform just two times per season.
San Francisco hasn't changed jerseys since the 2009 season, and has never before worn alternates.
With the offseason departure of head coach Jim Harbaugh for Jim Tomsula, the alternate uniforms will help ring in a new era in the Bay Area.
The 49ers open the season against the Vikings at Levi's Stadium on ESPN's Monday Night Football at 10:20 p.m. ET.
- Kayla Lombardo