Background: Pain relief in children is a complex issue, partly an ethical dilemma and due to a lack of nursing competence. There are few studies regarding prehospital care encounters with children in pain. Aim: The aim of this study was to describe nurses’ experiences in prehospital care encounters with children in pain and the specific related challenges. Method: This study has a qualitative design. Eighteen Swedish nurses participated in three focus group interviews analysed using qualitative content analysis. Findings: The findings consist of a theme, “A challenge to shift focus and adjust to the child”, and three categories describing prehospital care encounters with children in pain: “Being receptive and focusing on care,” “Developing a trusting relationship,” and “Providing professional nursing care.” Caring for children in pain was stressful for the nurses. The nurses described how they had to shift focus and used different methods to build trust, such as playfulness, making eye contact, attracting curiosity, and using the parents to create trust. The also had to adjust to the child regarding dosages and materials. Conclusion: Nurses has to be practically, mentally, and theoretically prepared to care for children with prehospital pain. It is essential to evaluate the administration of adequate pain relief to children, and more evidence-based knowledge is necessary concerning the different modes of administering pain-relieving drugs to prehospital children.