The CNO cycle is one of the fundamental processes of hydrogen burning in stars. The first reaction of the cycle is the radiative proton capture on ¹²C and the rate of this ¹²C(p,𝛾)¹³N reaction is related to the ¹²C/¹³C ratio observed e.g. in the Solar System. The low-energy cross section of this reaction was measured several times in the past, however, the experimental data are scarce in a wide energy range especially around the resonance at 1.7 MeV. In the present work the ¹²C(p,𝛾)¹³N cross section was measured between 300 and 1900 keV using the activation method. This method was only used several decades ago in the low-energy region. As the activation method provides the total cross section and has uncertainties different from those of the in-beam 𝛾-spectroscopy technique, the present results provide a largely independent data set for future low-energy extrapolations and thus for astrophysical reaction rate calculations.