In view of their commitments to the Convention on Biological Diversity, many countries are deciding how to increase their Protected Areas (PAs) by 2030. However, not all proposals are entirely new, with some having colonial roots. Colonial PAs have histories related to land dispossession and loss of natural resource rights. These PAs were created in “frontier spaces”, which upended customary property systems, social dynamics, and disregarded customary rights. Territorialisation is the strategic use of bounded space to control resources. We use territorialisation to understand the links between colonial and modern PAs. In some cases, modern PA proposals propose to resurrect colonial reserves. Through the lens of territorialisation over time, we trace the creation of the Mont Fouari colonial hunting reserve complex (Gabon/Republic of Congo), the Reserve Floristique de Yangambi (Democratic Republic of Congo-DRC), Lomami National Park (DRC), and the Plateaux Batéké National Park (Gabon). Community consultation was non-existent when many PAs were created, but newer ones now consider it. Despite these new efforts, we show how colonial territorialisation through the creation of reserves lives on in new proposals for many modern PAs. We reflect on the consequences of these proposals, and whether creating or expanding PAs with colonial histories is good for people and biodiversity.