The objective of the research is to analyze whether the elaboration and implementation of biodiversity offsetting policies depend on the quality of spatialized ecological data. We compared the availability and use of such data in Colombia and France, at various stages of the process: (i) anticipation (policy elaboration), (ii) planning, and (iii) monitoring and control. We show that spatialized ecological data are used to implement offsetting policies (France), but may also be a tool to develop such policies, in particular through the elaboration of predetermined ratios based on available scientific data (Colombia). We also show, based on geographical, ecological and legal aspects of the data, that the geographical characteristics of a country and its legal framework are an important determinant of the efficiency of offsets. Where the offset ratio is high, the feasibility of the offsetting will likely depend on whether preservation, and not only restoration, measures are allowed, but also on space finiteness and availability. There is also a necessity to balance the need for legal certainty that predetermined ratios provide with policy effectiveness in terms of no net loss of biodiversity. We emphasize the need for a regularly updated public portal that centralizes environmental data. Further, we note that an important caveat is to ensure that the guidance purpose of offsetting-related land-use planning instruments is not diverted and used to replace fieldwork. We also show that the legal requirement of ‘ecosystem’ (Colombia) vs ‘ecological’ (France) equivalence has practical consequences.