This Special Issue addresses the intersections of outdoor recreation, nature-based tourism, and sustainability. Outdoor recreation and nature-based tourism provide essential benefits to individuals, communities, and society and thereby contribute to sustainability. Equitable provision of opportunities, cultural variations in desired experiences, barriers to outdoor recreation, and diverse perceptions of both nature and recreation add to the complexity in outdoor recreation and nature-based tourism service delivery. Outdoor recreation and nature-based tourism occur within a socioecological system with feedback loops to changing social, economic, technological, and ecological conditions. On a global scale, climate change and other disturbance factors are impacting ecosystems and opportunities, increasing the importance of adaptation strategies for longer-term planning. Population growth and regional shifts in demographics and distribution (e.g., urbanization), as well as socioeconomic trends, affect who engages in outdoor recreation and nature-based tourism, opportunities sought, nature access, and governance of outdoor services. Overall the complexity of sustainable outdoor recreation and tourism may suggest a need for different approaches to service delivery, culture change among service providers and managers of natural spaces, and novel approaches to inclusive governance and shared stewardship. Given the clear importance of outdoor recreation and nature-based tourism to society, we invite you to consider this initial introduction to our assembled collection, which is meant to advance our understanding of the intersections of outdoor recreation, nature-based tourism, and sustainability.