The polymorphic rhodium-bismuth compound RhBi2 has attracted interest owing to its non-trivial topological electronic states. We report the growth of single crystals of both α- and β-RhBi2 and a study of their physical properties at low temperatures and ambient and high pressures beyond 40 GPa. At ambient pressure, β-RhBi2 is a metal with a low density of states at the Fermi level, whereas α-RhBi2 is a semimetal with large magnetoresistance (~500%). Point-contact Andreev-reflection spectroscopy demonstrates induced superconductivity for both phases. By applying pressure, we observe the emergence of superconductivity at P ≈ 8 GPa in β-RhBi2 and at p ≈ 20 GPa in α-RhBi2, with the critical temperature Tc exhibiting a dome-shaped dependence on pressure in both phases. The maximum values of Tc are 6.6 K at p ≈ 13 GPa for β-RhBi2 and 3.7 K at p ≈ 24.2 GPa for α-RhBi2. Synchrotron X-ray diffraction studies show that the crystal structure of α-RhBi2 remains stable over the entire investigated pressure range.In contrast, β-RhBi2 undergoes a transition from a triclinic to a tetragonal structure (γ-RhBi2) at p ≈ 13.5 GPa, accompanied by the attainment of the maximum value of Tc..