TOI-5388 is a cool M-dwarf (about 0.29 solar masses, 3,440 K, 0.30 solar radii), 18.5 light-years from Earth. TOI-5388.01 is a 2.2-Earth-mass planet, with an orbital period of 2.6 days, and an equilibrium temperature near 488 K, discovered in 2024 via transit. The planet was found when it crossed the face of its star, producing periodic dips in brightness that reveal its size and orbital period to space-based photometry. At 1.0 Earth radii, TOI-5388.01 is a compact world comparable in size to rocky planets in our Solar System.