Studies have shown that nature exposure is associated with a more positive body image, but field studies remain relatively infrequent. Here, we examine the impact of a woodland walk on an index of state positive body image (i.e., state body appreciation), as well as dispositional and environmental determinants of body image improvements. Eighty-seven Polish women went for a walk in Cygański Las, an ancient woodland, and completed a measure of state body appreciation before and after the walk. As hypothesised, state body appreciation was significantly higher post-walk compared to pre-walk (d = 0.56). Additionally, we found that the trait of self-compassion—but not the traits of connectedness to nature, perceived aesthetic qualities of the woodland, or subjective restoration—was significantly associated with larger improvements in state body appreciation. These results suggest that even relatively brief exposure to nature results in elevated state body appreciation, with the dispositional trait of self-compassion being associated with larger effects.