Objectives: Vessels constitute a unique type of workplace, primarily due to their operation in non-standard external environments and the spatial constraints inherent to their design. As a result, onboard working conditions play a critical role in ensuring the health and safety of crew members. This study aimed to evaluate the subjective assessment of working conditions among seafarers and to analyze the relationship between perceived en- vironmental burdens and job satisfaction. Material and Methods: The study was conducted on a group of 300 employees working on inland, port, coastal, and Baltic Sea vessels. A questionnaire survey was used to collect data on the subjective evaluation of working conditions and the perceived intensity of environmental factors such as noise, vibrations, and microclimate. Correlations between these factors and job satisfaction were analyzed. Results: The assessment revealed that 84% of surveyed seafarers rated their overall working conditions positively. However, environmental burdens were prevalent: noise (82%), vibrations (71%), and microclimate (65%) were identified as the most common nuisances. A negative correlation was observed between the perception of environmental burdens and job satisfaction. Conclusions: Although the general assessment of working condi- tions on vessels was positive, noise, vibrations, and microclimate remain significant issues affecting the well-being and job satisfaction of seafarers. Preventive measures aimed at mitigating these burdens may contribute to improving occupational health and safety onboard vessels. Int J Occup Med Environ Health. 2026;39(1)