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Steady-state seawater–groundwater interactions are simulated for homogeneous, anisotropic unconfined coastal aquifers using the two-dimensional numerical model MARUN. The spatial salinity distributions are approximately independent of the horizontal hydraulic conductivity K x when α L K x K z ⩾ 10 −6 m 2 /s. Here K z is vertical hydraulic conductivity and α L is longitudinal dispersivity. Both the fresh groundwater discharge rate Q f and seawater recirculation rate Q s depend linearly on K x . These conclusions are validated by a semi-analytical method. The increase of anisotropy ratio pushes the saltwater wedge interface seaward and reduces Q s . The increment of the longitudinal/transverse dispersivity ratio with fixed longitudinal dispersivity decreases the slope of isosalines and Q s . When the seabed slope angle θ increases from 0.01 to π /2, the freshwater–seawater interface moves landward. The increment of θ increases Q s slightly when θ < π /4 and reduces Q s when θ > π /4. The inland recharge rate Q f is independent of the seabed slope. [ABSTRACT FROM AUTHOR]