Sector 9 is a longboard manufacturer and subsidiary of Billabong International. The company was started in La Jolla, California in 1993 by cofounders Steve Lake, Dave Klimkiewicz, Dennis Telfer, and Tal O'Farrell. Sector 9 is currently headquartered in San Diego, California.
Sector 9 specializes in longboards for surfing, longboarding, and snowboarding. Their main focus is on hard goods, but they also offer a range of soft goods.
Billabong International acquired Sector 9 in 2008.
Sector 9 sponsors numerous different skateboarders and surfers, including Joel Tudor.