Physical literacy has been shown to relate to children's engagement in physical activity. However, it is unclear whether this relationship extends to adults. A two-phase cross-sectional study was conducted to examine whether physical literacy relates to physical activity in adults. In phase one, 225 participants reported their perceived levels of physical literacy using the Physical Literacy in Adults Scale (PLAS) and their physical activity behaviours using the International Physical Activity Questionnaire. In phase two, 59 participants wore an accelerometer to provide a device-based assessment of physical activity before completing the PLAS. A series of bivariate regressions were conducted to assess the relationship between physical literacy and physical activity. Physical literacy was a significant predictor of self-reported moderate to vigorous physical activity (MVPA) and total physical activity. However, scores on the PLAS did not predict light intensity self-reported physical activity. For device-based assessment of physical activity, physical literacy was a significant predictor of MVPA, but did not predict light or total physical activity. These findings indicate that physical literacy relates to physical activity, particularly MVPA. Differences in findings between self-report and device-based assessment warrant further consideration. Future research should continue to assess the role of physical literacy across physical activity types (e.g. leisure time, work related) and intensities.