Natural environments (NE) are promoted as places that support physical activity (PA), but evidence on PA distribution across various types and sizes of NE is lacking. Accelerometers and GPS-devices measured PA of Dutch general population adults aged 45–65 years (N=279). Five NE types were distinguished: ‘parks’, ‘recreational area’, ‘agricultural green’, ‘forest & moorland’, and ‘blue space’, and four categories of size: 0–3, 3–7, 7–27, and ≥27 ha. Modality (i.e. spatially concentrated PA, walking, jogging, and cycling) and intensity (i.e. sedentary behavior, LPA, and MVPA) of PA varied significantly between NE types. Compared to parks, less sedentary behavior and walking but more spatially concentrated PA was observed in recreational areas and green space. Cycling levels were found to be significantly lower in recreational areas and forest & moorland, but higher in blue space as compared to parks. Larger sized NE (≥7 ha) were associated with higher levels of MVPA, walking, jogging and cycling. Insight in which environments (according to type and size) facilitate PA, contributes to the development of tailored PA promoting interventions with ensuing implications for public health. © 2017 The Authors