The shape of coasts and the seafloor provides a wealth of geomorphological information that reflects the time-integrated effects of tectonic, sedimentary, oceanographic, and volcanic processes. Many such processes are hazards to coastal populations and offshore infrastructure, and their study constitutes key objectives of national and international research programs. This session aims to examine the causes and consequences of geomorphic processes shaping coastal and underwater landscapes, including erosional and depositional processes, sediment transport, coastal and submarine landslides, volcanic activity, faulting and folding. The general goal of the session is to bring together researchers who characterize the shape and evolution of past and present coastal and seafloor landforms, seek to understand the surface and sub-surface processes at work and their impacts, and use topographic, geophysical, and sedimentary data for modeling coastal and marine change. Research of any scale, exploring datasets that range from satellite imagery to ultra-high-resolution bathymetry, as well as field-based research and modeling, is welcome.