Summary Hydrothermal fluid circulation through porous Earth materials is an important physical phenomenon occurring in both submarine and continental environments. Irregularly interconnected discrete fractures are pervasive in nearly all Earth materials, providing preferential paths for fluid flow and controlling the circulating fluid patterns. Most mathematical algorithms addressing hydrothermal convection problems treat rocks as πecewise continuous media. The representation of local, large changes in permeability requires a high level of discretization for accurate results and a corresponding large number of unknowns. The alternative is to incorporate fractures discretely through special adaptation of the numerical code. We adopt this approach to solve the coupled, time-dependent heat and fluid transport differential equations using the finite element method. The final algorithm is validated against both an analytical solution and νmerical solutions from a complementary but less general finite difference scheme. Case studies of some simplified fractured models indicate that fractures can induce and maintain hydrothermal fluid circulation in media which would otherwise be passive. Fracture location can control both convection pattern and vigour in a closed system. Discrete fractures can also significantly change an established convection pattern. Multiply fractured porous media are comparable with the homogeneously aniso-tropic media in the numerical solutions if the effective average horizontal and vertical permeabilities are kept the same.