Natural rubber (NR) is employed in a multitude of industries beyond the manufacture of tyres, including the production of earthquake-resistant isolators, bridge bearings, gaskets and hoses. However, NR is susceptible to environmental aggressors such as temperature, oxygen, ozone and UV light, which can lead to degradation and cracking. In particular, ozone induces rapid visible cracking in NR due to reactions with its double bonds. Antiozonants, such as diamines and paraffin wax, are commonly employed to mitigate cracking, yet challenges persist, particularly under cyclic deformation. This study examines the impact of antiozonants on crack evolution in NR subjected to ozone exposure. Artificial ageing processes are developed to simulate accelerated ageing at ground-level conditions, varying ozone concentrations and ageing times. Crack depth evolution is monitored using optical microscopy. The results demonstrate that while antiozonants delay cracking, prolonged exposure leads to increased crack depths, particularly under cyclic strain. Simulation models predict crack growth as a function of ageing time and ozone concentration, revealing the effectiveness of antiozonants at different environmental conditions. The study highlights the complexity of NR ageing dynamics and offers insights for optimising antiozonant usage to enhance material durability. Further research recommendations are outlined to address extrapolation challenges to lower ozone concentrations.