Background: Lack of regular physical activity is a significant risk to health. The aim of this study was to objectively measure the levels and patterns of activity of adults with intellectual disabilities, to inform the design of studies aimed at increasing activity and health in this population. Materials and Methods: Interviews were conducted with 62 community-based adults with mild to moderate intellectual disabilities at the start and at the end of a 7-day period of physical activity/inactivity measurement using an activity monitor. Results: Forty-one (66%) participants wore the activity monitor at least 5 days. Of these, only 11 (27%) achieved the recommended 10 000 steps per day, and only six (15%) were achieving the recommended greater than or equal to 30 min of moderate/vigorous activity at least 5 days per week. Conclusions: Adults with mild to moderate learning disabilities have low levels of physical activity.