This review assesses available evidence on the frequency of and trends in depression and suicide among seafarers. Investigations of depression and suicide are scarce and the findings are inconsistent, they do, nevertheless, show indications of improvement although some recent case series do indicate that suicide remains a problem. A review of additional indicators for mental distress and lack of wellbeing supports the decline in frequency of problems, but nuances this in terms of the relative risks in different groups of seafarers, showing internal variations in the frequency of mental health issues among seafarers, with markers such as rank, type of voyage, gender, age, nationality and crew multiculturalism being relevant variables. The methodological limitations that hinder the understanding of depression and suicide in the maritime sector are identified.