Outdoor play has markedly declined amongst Australian children over recent decades. For preschool-aged children, outdoor play is an important source of daily physical activity, with the home yard being a common setting for such activity in this young age group. This study estimated the associations between time spent in outdoor play in the home yard of 1,558 children aged 2-5 years in Perth, Western Australia, and vegetation cover in the home yard, identified via high-resolution remote sensing data from the Urban Monitor Program. Shrub and tree cover were found to be positively associated with outdoor play. Stratified analyses showed that these relationships varied by parent education level, with all vegetation types being positively associated with outdoor play in the most educated group, but only tree cover showing a positive association in the lower parent education group. Yard size was also found to be positively associated with outdoor play. While this study provides evidence that larger yards with more vegetation may facilitate outdoor play in preschoolers, Australia’s changing residential landscape towards smaller lot sizes and larger homes emphasises the vital role of neighbourhood green space as a setting for outdoor play, particularly in more disadvantaged areas.