The safe assessment of site conditions for all types of marine installations and infrastructure requires a detailed understanding of the shallow subsurface and the changes therein over the lifetime of the areas of interest. This essential objective can only be achieved through the extensive use of complementary geophysical methods and monitoring approaches, as well as a proper, data-driven integration of geotechnical, geomechanical, metocean and geophysical data and models. The 4th conference will cover the widest range of topics of applied high-resolution geophysics in all types of aquatic settings.