AbstractRecent planetary data and geophysical modeling suggest that hydrothermal activity is ongoing under the ice crust of Enceladus, one of Saturn's moons. According to these models, hydrothermal flow in the porous, rocky core of the satellite is driven by tidal deformation that induces dissipation and volumetric internal heating. Despite the effort in the modeling of Enceladus' interior, systematic understanding—and even basic scaling laws—of internally heated porous convection and hydrothermal activity are still lacking. In this article, using an idealized model of an internally heated porous medium, we explore numerically and theoretically the flows that develop close to and far from the onset of convection. In particular, we quantify heat‐transport efficiency by convective flows as well as the typical extent and intensity of heat flux anomalies created at the top of the porous layer. With our idealized model, we derive simple and general laws governing the temperature and hydrothermal velocity that can be driven in the oceans of icy moons. In the future, these laws could help better constraining models of the interior of Enceladus and other icy satellites.