The increasing complexity of infrastructures and densely built-up areas requires a proper registration of the legal status (private and public), which can only be provided to a limited extent by the existing 2D cadastral registrations. The registration of the legal status in complex 3D situations is investigated under the header of 3D Cadastres. This publication, containing 13 selected contributions on 3D Cadastre, addresses the following areas: 1. 3D Cadastre operational experiences (analysis, LADM based, learning from each other, discovering gaps), 2. 3D Cadastre cost-effective workflow for new/updated 3D parcels = 4D (part of whole chain: From planning/design/permit in 3D, to registration/use in 3D), 3. 3D Cadastre web-based dissemination (usability, man–machine interfaces, including mobile/AR), 4. legal aspects for 3D Cadastre, best legal practices in various legislation systems, focus on large cities, including developing countries, 5. 3D data management, and 6. visualization, distribution, and delivery of 3D parcels.