Injurious acts that fall within the rules in competitive sports lack unlawfulness or can be justified. The rationales of justifying such injurious acts include the theory of legitimate professional conduct, the theory of acceptance of dangers (quasi consent) and the principle of superior interest. Acts that break sports’ rules, causing serious injuries, are usually dealt with by the internal regulations of the sports industry, following the principle of ‘judicial non-intervention’. However, industry self-regulation does not eliminate the application of law. It is necessary for criminal law to intervene where the rule-breaking acts have caused serious harm to the protected interests. To achieve the protective goals of offences against the person, actors who break the sports rules causing serious injuries or death or who deliberately take advantage of sports rules to injure others should be criminally liable for certain offences depending on their subjective mental state.