Generic global conservation targets lack the ambition required for certain habitats of critical value for biodiversity and human well-being. Developing more challenging targets for such habitats may offer a solution. Mangrove forests provide an example: any and all future loss will have negative repercussions, while many impacts could be reversed through extensive restoration. The Global Mangrove Alliance, an international grouping of 100 civil society and academic partners, has set goals to halt anthropogenic losses, accelerate restoration and greatly enhance protection by 2030. Using global-scale data, we estimate that achieving these goals will avoid losses of some 1500 km2; restore some 4000 km2; and secure an additional 36 000 km2 of mangroves under effective and equitable protection. Multiple benefits will follow, and we present values for carbon storage gains and avoided losses. Global datasets can guide broad approaches, while quantifying the challenges and benefits provides inspiration and impetus for change.