Seamounts contribute to globally significant hydrothermal fluxes, but the dynamics and impacts of fluid flow through these features are poorly understood. Numerical models of coupled heat and fluid flow illustrate how seamounts induce local convection in the oceanic crust. We consider idealized axisymmetric seamounts and calculate mass and heat fluxes by using a coupled heat- and fluid-flow model. By using P. Wessel's global database of ∼15,000 seamounts identified through satellite gravimetry, we estimate that the mass flux associated with seamounts is ∼1014 kg/yr, a number comparable to estimated regional mass fluxes through mid-ocean ridges and flanks. In addition, the seamount-generated advective heat flux may be locally significant well beyond the 65 Ma average age at which advective lithospheric heat loss on ridge flanks ends. These flows may be important for facilitating geochemical exchange between the crust and ocean and may affect subseafloor microbial ecosystems.