Outreach by scientific researchers in school classrooms often results in widespread benefit for learners, classroom teachers and researchers. This paper presents a consideration of these benefits using two case studies in the Geography, Earth and Environmental Sciences (GEES). In each case, different school classroom-based activities were designed by scientists, but were improved by input from educational professionals, which helped to maximize the mutual learning experiences and to ensure the quality of the content and its delivery. Each case study suggests an improvement in scientist’s working knowledge of best practices for classroom-based outreach activities, which can translate to improved practices for University-level teaching, among other tangible career-relevant benefits. Despite these benefits, these projects highlight the well-established need for improved training for researchers in effective outreach practices, increased value on programme evaluation, and the growing need for meaningful professional recognition for researchers involved in these important, and ever-growing, outreach activities.