Hydrogen is gaining traction as a potential substitute for traditional fuels, offering a viable solution in significantly reducing carbon emissions in the heavy-duty transport industry. Engines powered by hydrogen could be instrumental in creating a more sustainable future, particularly in the heavy-duty vehicle sector, which is predominantly dependent on internal combustion engines (ICEs) fueled by carbon-based fossil fuels. While hydrogen engines are advantageous because of their near-zero CO2 emissions, they do generate some pollutants, including nitrogen oxides (NOX) and trace amounts of particulate matter due to unwanted side-reactions and lube-oil consumption respectively. Therefore, the implementation of an Exhaust Aftertreatment System (EAS) remains necessary for these engines to adhere to the emission standards outlined in the upcoming Euro 7 regulations. It’s crucial that the EAS not only meets emission standards at the beginning of its life but also retains its effectiveness throughout the vehicle’s lifespan, ensuring consistent emission reduction even as it ages. This research delves into the performance of the EAS in a hydrogen engine exhaust over a period of durability testing. The study examined the EAS in the exhaust system of a 13L class inline-six heavy-duty hydrogen engine, evaluating its ability to convert emissions under various driving conditions, with a focus on meeting Euro 7 emission standards. The EAS was also subjected to approximately 500 hours of durability testing under a range of operating conditions, including various steady-state and transient cycles that mimic real-world usage. The findings offer valuable understanding into how the EAS’ performance evolves over the testing period. They also highlight anticipated challenges in achieving Euro 7 compliance over the vehicle’s lifespan and suggest possible strategies for overcoming these obstacles.