Pursuing development and conservation goals often requires thinking and planning across terrestrial, freshwater and marine realms because many threats and social-ecological processes transcend realm boundaries. Consequently, effective conservation planningmust consider the social and ecological links between realms and follow a cross-realm approach to allocate land/water uses and conservation actions to mitigate cross-realmthreats and maintain cross-realm ecological processes. Cross-realm planning requires integrating multiple objectives for conservation and development, and assessing the potential co-benefits and trade-offs between themunder alternative development scenarios. Despite progress in cross-realmplanning theory, fewfully-integrated and applied cross-realmplans exist. The gaps between research and implementation are not unique to cross-realm planning, but are accentuated by the complexity of spatial decision-making entailed. Based on a collaborative process including scientists, resource managers and policy-makers, we developed an operational framework for crossrealm planning based on up-to-date thinking in conservation science, but offering practical guidance to operationalise real-world planning. Our approach has a strong theoretical basis while addressing the visions and needs of decision-makers. We discuss the foundations and limitations of current approaches in crossrealm planning, describe key requirements to undertake this approach, and present a real-world application of our framework.