The tightening of emission regulations in major global markets, such as the European Union’s requirement for a 45% reduction in CO2 emissions for new heavy-duty vehicles by 2030, necessitates innovative solutions in heavy-duty drivetrains. Besides battery electric powered trucks, hydrogen internal combustion engines (H2 ICEs) emerge as a promising mid-term technology for CO2 reduction, leveraging existing internal combustion engine infrastructure while benefiting from the same hydrogen distribution systems as fuel cell electric vehicles (FCEVs). NGK’s advanced filter technology, traditionally used for diesel and gasoline engines particulate emission reduction, are demonstrated effectiveness in H2 ICE application. Two emission control system designs, incorporating uncoated filters with different features and SCR on filter, were evaluated for their ability to reduce primary and secondary particulates as well as NOx emissions on a hydrogen combustion demonstrator engine. The tailpipe emission results may provide guidance in future H2 ICE emission control system design. This study highlights the variability in particulate emissions during drive cycles with a hydrogen combustion engine and the potential for high secondary particulate emissions from urea dosing, which could challenge compliance with EU7 standards without a particulate filter.