Documentation and conservation of underwater cultural heritage (UCH) are crucial to preserving humankind’s history and traditions, safeguarding tangible testimonies of past human life while ensuring its accessibility to future generations. The TECTONIC (Technological Consortium TO develop sustainability of underwater Cultural Heritage) project is promoting an intersectoral collaboration between academic and non-academic professionals (i.e., archaeologists, conservators, geologists, engineers, etc.) working on different topics related to UCHs, to find solutions to the issues still existing in the field. The overall aim is the exchange of skills for the improvement and assessment of innovative materials and techniques to develop solutions and marketable products for the conservation and management of the UCH, sustainably. To achieve its overall aim, TECTONIC is undertaking activities driven by the following objectives: (a) the study, documentation, and mapping of selected UCHs; (b) the creation of decision-support tools for UCH risk assessment in a changing environment; (c) the initiation of conservation studies and protocols for conservation activities; (d) the development of open and low-cost robotic solutions for the inspection of UCH; and (e) the raising of public awareness and knowledge about UCH. All the objectives are devoted to stimulating new sustainable ideas that would bring the growth of cultural tourism and the development of new marketable products by capitalizing on the research results.