New collision integrals and transport cross sections for O(3P)–O(3P) interaction are reported in the 300–30000 K range. Those values are based on a new set of potential energy curves (PECs) calculated with the multireference configuration interaction method. The results of the classical and semiclassical WKB (Wentzel–Kramers–Brillouin) methods are compared, excellent performance of the classical approach is shown (discrepancy much lower than 1% even at room temperature). In particular, the classical and WKB methods agree very well for the repulsive potentials effectively reducing overall uncertainty.