The remote, isolated, confined, and safety-critical environment of seafaring exposes seafarers to a very specific assortment of stressors. Research suggests that seafarers as a professional group are amongst those at high risk for stress and associated mental health conditions. This article explores positive psychology as an approach to supporting wellbeing at sea. Positive psychology may support health, positive attitudes and productive work behaviour; however it cannot and should not be employed as a means of inoculating seafarers against the negative consequences of fundamentally unreasonable work practices. Rather, positive psychology can help seafarers thrive in an overall context that recognises and enacts the benefits of a positive and reasonable work environment. Recommendations are made for future research regarding online or computer-based positive psychology interventions and training, and research on maritime health at the systems level.