According to Korea Seafarer’s Statistical Yearbook, as of 2020, seafarers’ occupational accident rate of 9.49% was 19.4 times higher than shore workers’ occupational accident rate of 0.49% according to the Analysis of the Status of Industrial Accident in 2020 published by the Ministry of Employment and Labor, the accident rate related to safety and health on board ships is in a very serious level. In addition, the accident rate of Korean seafarers of 11.24% (as of 2019) is 6.8 times higher than the accident rate of Japanese seafarers of 1.66% (as of 2019). This suggests that it is urgent to improve legislation related to seafarers’ accidents to reduce the accident rate of seafarers in the Republic of Korea. To raise the level of safety and health on board ships for the prevention of occupational accidents of seafarers, it is preferentially necessary to improve related legislation. Legislation for the protection of shore workers has been completed through the full revision of “Occupation Safety and Health Acts” while there are institutional gaps, like the lack of standards for safety and health on board ships for seafarers. Thus, it is necessary to seek institutional legal measures for reducing the high accident rate of seafarers. However, in order to improve standards for safety and health on board ships for the prevention of occupational accidents of seafarers, not only the improvement of related legislation is important but also the roles of shipowners and seafarers who comply with them are important. In particular, to prevent the occupational accident of seafarers, shipowners shall comply with the obligations relating to the safety and health on board a ship and it is also essential for seafarers to work together with shipowner in taking such preventive measures. Thus, as for measures for reducing the accident rate of seafarers, this study aims to examine the present legislation on the state, shipowners, and seafarers for safety and health on board ships and then derive measures for the improvement relating thereto. As a result of this study, the following improvements were proposed. First, as measures for improving safety and health on board ships from the prospective of the state, the following points were derived: ➀ measures for improving the survey of occupational accidents, injuries, and diseases of seafarers (the definition of an occupational accident, the improvement of reporting standards, contents, and procedures, and the improvement of investigating range, and contents), ➁ measures for improving statistics on the occupational accidents, injuries and diseases of seafarers (the clarification of the contents of statistics), and ➂ measures for improving the safety and health of seafarers of fishing vessels with gross tonnage of less than 20 tons (measures for the integration of legislation and competent department through legislating an independent Act). Second, as measures for improving safety and health on board ships from the prospective of shipowners, this study clearly stated that shipowners are the ones complying with the duty of care for safety in seafarers’ employment contract on the safety and health on board ships and derived the necessity of the improvement of shipowners’ role to raise the level of safety and health on board ships by actively participating in reviews for revising standards for safety and health on board ships. Third, as measures for improving safety and health on board ships from the prospective of seafarers, this study suggested that seafarers’ duties (safe care for a third party, duty of reporting hazards, and duty to take caution, etc.) should be expanded so that seafarers could independently and actively participate in the prevention of the occupational accident of seafarers, the duty of care for safety should be explicitly introduced in the Seafarers’ Act for seafarers to enable them to play positive and key roles in observing and implementing the safety and health standards, and seafarer claims should also be admitted for the case of breaching the duty of care for safety by shipowners. Last, despite improvements by the implementation agent to increase the level of safety and health on board ships, this study found that it would be necessary to have a special law (Laws for safety and health on board ships and accident prevention) to prepare more comprehensive legislation on the safety and health on board ships for the prevention of the occupational accident of seafarers, and derive the concept, role and main content of the special law.