The Southern Ocean (SO) south of 35°S represents a small source of natural inorganic carbon for the atmosphere but a major sink of anthropogenic carbon. The magnitude of the total (natural plus anthropogenic) carbon sink strongly depends on the rate at which carbon is subducted below the mixed layer. We use a global ocean model at eddying resolution under preindustrial and historical conditions to provide a detailed view of total and anthropogenic dissolved inorganic carbon (DIC) pathways across and within the time-varying mixed layer of five physically consistent regions. Within each region, subduction fluxes at the mixed layer base are decomposed into advective and diffusive contributions to determine which process dominates. Total DIC is found to be obducted south of the Antarctic Circumpolar Current (ACC), transferred northward within the mixed layer and subducted north of the ACC. This results in a net obduction of 11.2 PgC/year, with advective processes dominating the total transfer (67%). Anthropogenic carbon is taken up in all regions but anthropogenic DIC is mainly subducted north of the ACC, the carbon taken up in the south being advected northward within the mixed layer before being subducted. This subduction (1.05 PgC/year) is achieved mainly through advection and diffusion, which dominate respectively north and south of the Subantarctic Front. Advective subduction fluxes show strong zonal variations and are increased near major topographic features and boundary currents. Our results suggest that we need to untangle advective and diffusive pathways regionally in order to understand how carbon subduction will evolve.