Environmental determinants of health are receiving growing attention in the literature, although there is little empirical research in this area. The Study on Environmental and Individual Determinants of Physical Activity (known as the SEID project) was a social ecological project that examined the relative influence of individual, social environmental and physical environmental determinants of recreational physical activity. It involved a community survey of 1803 healthy workers and home-makers aged 18-59 years living in a 408 km2 area of metropolitan Perth, Western Australia. Physical environmental determinants were mainly conceptualised as spatial access to popular recreational facilities. Overall, 59% of respondents exercised as recommended. Recreational facilities located near home were used by more respondents than facilities located elsewhere. The most frequently used facilities were informal: the streets (45.6%); public open space (28.8%) and the beach (22.7%). The physical environment's directs the influence on exercising as recommended was found to be secondary to individual and social environmental determinants. Nevertheless, accessible facilities determined whether or not they were used and in this way, support and enhance the achievement of recommended levels of physical activity behaviour by providing opportunities. The results suggest that access to a supportive physical environment is necessary, but may be insufficient to increase recommended levels of physical activity in the community. Complementary strategies are required that aim to influence individual and social environmental factors. Given the popularity of walking in the community, it is recommended that greater emphasis be placed on creating streetscapes that enhance walking for recreation and transport.