Mass Observing the Coronation of Charles III examines the activities and opinions of Mass Observers who experienced the first British coronation in 70 years, as well as the findings of Mass Observation investigators in several locations in the UK (including London) during the May 6th 2023 coronation weekend. Reports and photographs by mobile observers, as well as MO panelists' pre-coronation writings and day diaries for May 6th demonstrate the ways in which people think about and engage with contemporary monarchy in practice and concept. Following in the footsteps of the original 1937 Mass-Observation coronation publication, Mass Observing the Coronation of Charles III also charts social and cultural continuity and change over time, including the traditions of the ceremony itself and new events such as the Big Help Out.