•H induces voids and cracks at grain boundaries during rolling contact fatigue.•Mixed H embrittlement mechanism: localised plasticity and intergranular debonding.•Quantitative proof of increased void and crack populations upon H ingress. A ball-on-rod RCF tester was employed to investigate the failure mechanisms of hydrogen-rich rolling components. The formation of defects, voids and surface cracks is significantly facilitated in hydrogen-rich bearing steels. In samples with RCF cycles of 1.6 × 107, the void density in hydrogen-rich samples is about three times that of hydrogen-free samples, whilst their crack length density four times that of hydrogen-free samples. This is due to a higher stress intensity factor around inclusions which is altered by hydrogen. Further characterisation confirms that grain boundaries are preferential sites for void formation and crack propagation.