Hydrogen as a fuel for internal combustion engines (ICEs) presents a promising pathway towards achieving high-efficiency, carbon-free powertrains for future mobility. This paper explores the current status, potential, and challenges associated with hydrogen-powered internal combustion engines. Hydrogen combustion offers substantial reductions in CO2 emissions, but challenges persist, including NOx emissions, combustion stability, and the development of a comprehensive hydrogen infrastructure. The analysis delves into hydrogen’s unique combustion properties, which differ from traditional fuels and require advanced engine designs and innovative combustion strategies to optimise efficiency. Additionally, the paper evaluates the environmental implications, emphasising the role hydrogen ICEs could play in achieving the ambitious targets of the Paris Agreement and the European Green Deal. Although hydrogen ICEs present a promising alternative, their success depends on overcoming significant technological and economic barriers, as well as aligning with evolving regulatory frameworks. The research concludes that despite the perception of ICEs becoming obsolete in Europe by 2035, hydrogen ICEs remain a viable powertrain solution, particularly for heavy-duty vehicles (HDVs), where they may outcompete fuel cells due to lower production costs and superior performance. This positions hydrogen ICEs as a critical component in global decarbonisation efforts.