The frequency of home spatial activities (e.g., puzzles and blocks) correlates with young children's spatial skills, but causal evidence is limited. We addressed this issue by comparing the effects of a parent-led intervention aimed at increasing spatial activities to an active control targeting narrative activities (preregistered: https://osf.io/u7qrx). Parents of 80 4- and 5-year-old children were randomly assigned to either a spatial or narrative condition. Parents learned about the importance and malleability of spatial or narrative skills and engaged their children in spatial or narrative activities provided by the researchers for a month. Unexpectedly, the spatial intervention did not significantly enhance children's spatial skills or parents' motivational beliefs regarding children's spatial abilities. These findings do not support the hypothesis that spatial play causally influences children's skills. However, we note that the families in our sample had high socioeconomic status, and their children may have already benefited from rich spatial environments.