This study aimed to explore school nurses' experience of using physical activity on prescription with children in Swedish compulsory school. Semistructured interviews were conducted with 24 school nurses who had the educational qualification to prescribe physical activity. The analysis resulted in one overarching theme, "A delicate process of tailoring physical activity on prescription to a child's social context," and two categories: "Promoting joyful physical activity through individualization and support" and "Dealing with dilemmas and challenges," with related subcategories. The results demonstrate the importance of tailoring prescribed physical activity to each individual child, their living conditions, and the school context. In addition, they highlight the nurses' working conditions and collaborations as important prerequisites when initiating physical activity on prescription. In conclusion, the results suggest that school nurses perceive physical activity on prescription as a useful tool in the school context, but it needs to be tailored to each individual child.