Iron is the most widely used metal in the world. However, hydrogen embrittlement in steels-iron based alloys-is an important issue related to the safety of our infrastructure, such as railroads and bridges. Therefore, the prevention of hydrogen embrittlement in steels is necessary. In the present study, we demonstrate two novel methods for the prevention of hydrogen embrittlement in iron: one involves the low-energy implantation of helium, which is usually an element harmful to metals, into iron, the other is inducing damage to the iron surface by ion irradiation. In general, irradiation with high-energy particles leads to metal brittleness. In the former method, the driving force for hydrogen embrittlement in iron is weakened, in the latter method, hydrogen diffusion in iron is prevented because of trapping of hydrogen atoms in the vacancies produced by the irradiation. As a result, hydrogen embrittlement in iron was suppressed by both methods.