Children today spend an increasing amount of time indoors, depriving them of the benefits of a more active outdoor life. In Scandinavia, regularly performed teaching outside the classroom, known as "udeskole", is growing in prevalence. This paper examines experienced teachers' perceptions of "udeskole", with the aim of deepening our understanding of the factors that enable their practice. Ten in-service, degreed teachers from different schools participated, being interviewed individually. Data were thematically analysed and discussed within Deci & Ryan's Self-Determination Theory framework. The teachers' approach to their professional life is presented as a possible avenue for maintaining professional mastery in a school setting that is considered to be increasingly prescriptive and to have narrowing learning goals. The findings suggest two implications for policy. First, teachers' space for independent decision-making should be maintained. Second, an enhancement of networks between outdoor practitioners to enable them to share good practice should be prioritized.