TOI-3629 is a cool M-dwarf (about 0.63 solar masses, 3,870 K, 0.60 solar radii), 130 light-years from Earth. TOI-3629 b is a 0.26-Jupiter-mass companion, with an orbital period of 3.9 days, at 0.043 AU from its star, and an equilibrium temperature near 690 K, discovered in 2022 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. TOI-3629 b skims its star closer than Mercury orbits the Sun.