ObjectiveWe investigated grandparents' motivations and challenges for grandparent–grandchild outdoor play with their 3‐ to 5‐year‐old grandchildren.BackgroundOutdoor play benefits children's and older persons' mental and physical health. Thus, intergenerational outdoor play could benefit both grandparents and their younger grandchildren.MethodSemistructured interviews were conducted with 14 grandparents (seven grandmothers and seven grandfathers) from British Columbia, Canada, who lived in the same province as their grandchildren and who were fluent in English. Grandparents were recruited using a convenience, purposive sampling method with social media advertisements, posters in community centers, and word of mouth.ResultsUsing a thematic analysis, we identified six themes: (a) improving grandparents' and grandchildren's health, (b) supporting children's needs, (c) feeling positive emotions, (d) supporting family closeness, (e) aspiring to go outdoors together, and, (f) maintaining the relationship despite the COVID‐19 pandemic.ConclusionOur study emphasizes the importance of outdoor play for grandparents, especially as they develop their relationship with their young grandchildren. Outdoor play provides a unique opportunity for a health‐boosting activity that also strengthens the relationship and family bonds, and supports grandchildren's developmental needs.ImplicationsOur research can contribute to promoting outdoor play across the life span, and more specifically the benefits of outdoor play during early childhood and older adulthood.