Ductile shear zones are first-order fluid conduits in the crust, where fluids are hosted by grain boundaries, cracks and pores, all of which evolve during deformation. This evolution controls where fluid will migrate and interact with rocks. We only have a limited systematic knowledge of porosity and permeability generation in natural ductile shear zones and are thus unable to predict their syn-kinematic fluid transport properties. This shortcoming severely affects our assessments of fluid-mediated processes in plate boundaries. In this session we aim to explore the latest progress towards better understanding how fluids move in actively deforming ductile shear zones. We welcome contributions that focus on the dynamic evolution of fluid pathways and porosity, and the migration of fluids in rocks during ductile deformation, including tracking of fluids on multiple scales. Given the cross-disciplinary nature of the topic, we invite contributions from structural geology, metamorphic petrology, geodynamic modelling, isotope geochemistry, geochronology, economic geology and all other relevant disciplines and perspectives.