Accurate rotational–vibrational line lists for 31P14N and 31P15N in their ground electronic states are computed. The line lists are produced using an empirical potential energy curve obtained by fitting to the experimental transition frequencies available in the literature in conjunction with an accurate, high-level ab initio dipole moment curve. In these calculations, the programs DPOTFIT and LEVEL 8.0 were used. The new line lists reproduce the experimental wavenumbers with a root-mean-square error of 0.004 cm−1. The line lists cover the frequency range 0–51 000 cm−1, contain almost 700 000 lines each and extend up to a maximum vibrational level of v = 66 and a maximum rotational level of J = 357. They should be applicable for a large range of temperatures up to, at least, 5000 K. These new line lists are used to simulate spectra for phosphorus nitride at a range of temperatures and are deposited in the Strasbourg data centre. This work is performed as part of the ExoMol project.