Biodiversity conservation requires prioritization to be effective. Biodiversity hotspots and conservation planning identify where to focus conservation efforts, but it is unclear when conservation is most successful. Our goals were to: (a) investigate if hot moments for conservation occur, (b) calculate how important and prevalent they are, and (c) discuss what may catalyze hot moments for conservation. We analyzed the worldwide network of protected areas since inception, analyzing both all countries, and those 35 countries that contained at least 1% of either the total count or the total area protected globally. The evidence for hot moments for conservation was very strong. Among all countries, 44% protected more than half of their protected area in 1 year, and 61% did so in one 5-year period. The 35 countries that contain most of the protected area globally (77%) protected 23% and 49%, respectively, within 1 or 5 years. Hot moments often coincided with societal upheaval such as the collapse of the USSR or the end of colonialism. Conservationists need to account for hot moments for conservation to be most effective.