Mangroves are highly important, endangered species that provide many environmental services. This research examines changes in the spatial extent of mangrove forest cover in the protected area of Yum Balam, in Mexico using data for the years 1981, 2005, 2015 and 2020, obtained from government agencies, together with a review of the history of mangrove conservation and the recent land management plan for the area. Results show an early period of losses, followed by a period of relative stability, culminating in a mix of losses in areas close to the urban centres of Chiquila and Holbox. A comparative analysis using spatial data obtained from Global Mangrove Watch and through Google Engine revealed inconsistencies, but similarities in the overall trend. Overall, the management plan favours tourism, allowing economic development in some sub-zones. Monitoring mangrove cover is important to identify drivers of change, and to elaborate informed policies for mangrove conservation.