Lime mortars play a crucial role in European and global masonry construction, offering several advantages over cement-based alternatives. These include low water penetration, improved breathability, better moisture control, enhanced workability, and lower carbon footprint. Moreover, lime-based mortars are compatible with ancient masonry, making them essential for the conservation of heritage buildings. Initiated in 2021 and funded by the European Commission, the SUBLime Network is a collaborative effort involving six academic institutions, twelve partner organizations, and fifteen PhD students. Its primary goal is to train researchers across various scientific and engineering disciplines to develop sustainable innovation solutions for lime mortars and plasters. This encompasses both new construction projects and the preservation of historical structures. SUBLime’s focus areas include material characterization, numerical modeling of multi-physics behavior, functionality, and sustainability in lime use. The project emphasizes innovative approaches such as biomimetic and closed-loop recycling methods. Specific contributions encompass microstructural and chemical characterization, testing methodologies, simulation of microstructural development, understanding of phenomena like creep and shrinkage, and development of functional materials. These efforts align with current EU objectives on environmental performance, striving towards carbon neutrality and increased sustainability in construction practices.