Understanding the fate of colloids in porous media, such as rocks and soils, is crucial for environmental and geophysical applications including groundwater remediation. Colloids ranging from nanometres to micrometres in size –including nanoparticles (NP) – can remobilize non-aqueous phase liquids (NAPL) trapped by capillary forces. However, the multi-scale mechanisms driving colloid-induced mobilization, from microscopic interfaces to pore networks and field-scale processes, are poorly understood. This study addresses this gap using time-resolved 3D X-ray micro-tomography to investigate colloid transport, pore clogging and flow modification under transient conditions. The results will advance fundamental knowledge on multiphase flow and colloidal transport in porous media with broad applications in environmental science, emerging contaminants and the use of subsurface in energy transition (CO2/H2/geothermal).