The aim of the study is to examine the influence of national safety culture, sector safety culture and organizational safety culture on safety behaviours among Greek (N=99) and Norwegian (N=93) crewmembers on cargo vessels, and to discuss results in light of additional explanatory variables. We focus on three types of unsafe maritime behaviours: 1) Violations/risk acceptance, 2) Working under the influence of alcohol, or while being hungover, and 3) Non-intervention/non-reporting. Linear regression analyses indicate that organisational factors like demanding working conditions and organizational safety culture are the most important predictors of violations/risk acceptance and non-intervention/non-reporting. National safety culture is the most important predictor of respondents’ tendency to work under the influence of alcohol, or while being hungover. National safety culture is measured as descriptive norms and as values (“freedom to take risks at sea”). The study indicates that safety culture at different analytical levels influence different types of unsafe behaviours.