In California, 2.15 million adolescents (62.9 percent) do not engage in at least 60 minutes of physical activity five or more days per week. This policy brief uses data from the 2009 California Health Interview Survey to find that adolescents who visited a park in the past month and those who live in a park service area are more likely to meet this goal. Lower-income California adolescents are less likely to visit local parks and more likely to believe local parks are unsafe. Actions by state and local policymakers to increase park access and attractiveness, especially to underserved populations, may be an effective way to promote physical activity among California's adolescents.