The use of ethnographic approaches to study social settings has been steadily increasing over the last several decades. However, relatively few studies have been conducted with children, particularly in physical activity settings. This dearth of research may be due to the reported challenges of trying to 'fit in' in the world of children. This autoethnographic study provides insight into the approach utilised to conduct an ethnographic study with children and to become a 'friendly adult' in their world. The original six-month project focused on examining a cohort of 5--8year-old children to try and understand their engagement and relationship with physical culture. The project, conducted at a school in Victoria, utilised a range of ethnographic and child-centred methods to examine children's engagement in PE and on the playground. This autoethnographic exploration provided the primary author the ability to reflect on and unpack his ethnographic approach to gain a deeper insight into his role in the project. This study investigates the challenges and opportunities that the primary author faced in trying to study the lives of these children. These challenges and opportunities included, embracing and engaging with past experiences; balancing roles as a former teacher; and maintaining a 'friendly adult' role. Being accepted into the world of the children required navigating these challenges and using them as opportunities to engage with the children as the gatekeepers of the research. Exploring these challenges and opportunities provided significant insight into how to engage with children in ethnographic research and build trust and rapport. Unpacking this approach through autoethnography provides a guide for future researchers working with children.