Objectives. We assessed park use in Recife, Brazil, and differences in physical activity and occupation rates in public parks with and without the Academia da Cidade Program (ACP), which provides cost-free, supervised physical activity classes. Methods. We used the System for Observing Play and Recreation in Communities (SOPARC) in 128 targeted areas in 10 park sites (5 ACP sites, 5 non-ACP sites) to obtain data on the number of users and their physical activity levels and estimated age. Each area was assessed 4 times a day for 11 days over a 4-week period. Results. A total of 32 974 people were observed during 5589 observation visits to target areas. People using ACP parks were more likely to be seen engaging in moderate-to-vigorous (64% vs 49%) and vigorous (25% vs 10%) physical activity. Relatively more participants in ACP sites than in non-ACP sites were females (45% vs 42% of park users) and older adults (14.7% vs 5.7% of park users). Conclusions. On the basis of systematic observation, ACP appears to be a useful strategy in promoting park use and physical activity among the population in Recife.