Sedimentary basins along continental margins are dynamic environments. Fluids are generated at different depths and migrate through the sedimentary column. Many of the basins are characterized by piercement structures, sometimes reaching the surface where they manifest onshore or offshore as mud volcanoes, cold seeps, pockmarks, or hydrothermal systems. During the ascent fluids modify their composition through mineralogical and geochemical reactions. Other processes involve the formation and dissociation of gas hydrates as well as biological activities that thrive in many of these extreme environments. Furthermore, fluid flow is also affected by external forcing such as seismic and man-made activity. The understanding of fluid flow processes in continental margin sediments is a major research topic relevant for ecosystems, submarine slope stability, biogeochemical cycles and possibly climate change. To this session we invite contributions that present the results of recent geological, geophysical and geochemical field programs, modeling studies, and ocean drilling results that give insight into the geological, geochemical and biological processes governing fluid migration and its effects. This activity is related to the EU-COST action FLOWS (https://www.flows-cost.eu/home) which aims at a better understanding of how fluid flow and seepage relates to seismicity in transform type plate boundaries.