Spillovers can significantly reduce or enhance the net effects of land-use policies, yet there exists little rigorous evidence concerning their magnitudes. We examine how Costa Rica’s national parks affect deforestation in nearby areas. We find that average deforestation spillovers are not significant in 0–5 km and 5–10 km rings around the parks. However, this average blends multiple effects that are significant and that vary in magnitude across the landscape, yielding varied net impacts. We distinguish the locations with different net spillovers by their distances to roads and park entrances — both of which are of economic importance, given critical local roles for transport costs and tourism. We find large and statistically significant leakage close to roads but far from park entrances, which are areas with high agricultural returns and less influenced by tourism. We do not find leakage far from roads (lower agriculture returns) or close to park entrances (higher tourism returns). Finally, parks facing greater threats of deforestation show greater leakage.