Wearable cameras have been used to study health behaviours, but their utility in assessing third-party behaviours and the built environment is uncertain. This paper reports on the feasibility of using wearable cameras for this purpose in a study of sun-protective behaviours and shade availability during school lunch-breaks. The Kids’Cam study provided 168 children (aged 11–13 years), recruited from 16 randomly selected schools in the Wellington region of New Zealand, with wearable cameras. The devices automatically captured images every 7 s from the child’s perspective. Images captured during school lunch-breaks by a random sample of 15 children who took part during terms 4 and 1 (October 2014–April 2015) were selected and assessed for usability. The feasibility of studying third-party sun-protective behaviours and school shade availability was assessed for a subset of 320 images. Of the 3492 eligible lunch-break images, 96.4% were useable; the remainders were excluded due to obstruction, blurriness or unsuitable camera position. Overall, 1278 children and 108 shade structures were observed in the sample images. The use of shade, hats, sleeves, collars and sunglasses could be determined for 97.0%, 77.2%, 74.4%, 47.6% and 54.9% of children, respectively. All shade structures could be classified according to type, and canopy composition could be assessed for 95.4% of structures. Wearable cameras are a feasible tool for assessing sun-safety, particularly shade availability, hat wearing and shade use. This methodology could be used to objectively study other third-party health-related behaviours, and other features of the built environment.