Psychologists and psychiatrists worldwide are expressing concerns regarding the growing prevalence of mental health problems and the incidence of suicide in young adults. The reasons are seen in the extremely high tempo of social changes, information pressure, and values evolution in the younger generations, which are exposed to growing inequalities, loneliness and lack of social support. Poverty, social isolation, consumerism, hedonism, and unrealistic expectations of the future generate in the vulnerable part of the young adults inevitable frustrations, which give way to depression, anxiety, addictions, and suicide. This creates additional risks for the situation on board ships, both military and merchant, and requires greater efforts during pre-admission selection and in the course of the service or voyages. Suicides in the Navy are better registered than in the cargo fleet and are lower than in the same age and gender groups from the general population, and usually lower than in other types of forces. Data on suicides in the civilian maritime sector are less conclusive, but suggest it as a growing problem, especially considering stress on board. Recent studies revealed quite a lot of mental health problems in the merchant fleet crews, including depression, anxiety, and suicidal thoughts. Among the reasons such factor as “flag of convenience” strategy that implies lower standards, recruiting of the less trained and lower-paid workforce, multinational and multilanguage rotating crews, higher workload and stress and insufficient level of the pre-employment medical examination are mentioned. Recent trends in the mental health of the youth demand higher awareness both in the military ships and in the merchant fleet. We consider that more education and training aimed at mental health problems identification and stress-resilience promotion are needed both for the military and civilian staff on board. Better education of the whole personnel and “healthy ship” approach (better recognition of the crew members’ needs, attention to mental health problems, nutrition, physical activity, etc.) may be applied both for the Navy and merchant fleet.