Societies value the marine environment for its health-promoting potential. In this preregistered study, we used cross-sectional, secondary data from the Seas, Oceans, and Public Health In Europe (SOPHIE) and Australia (SOPHIA) surveys to investigate: (a) relationships of self-reported home coastal proximity and coastal visits with self-reported general health; (b) the potential of both to buffer income-related health inequalities; and (c) the generalizability of these propositions across 15 countries (n = 11,916–14,702). We find broad cross-country generalizability that living nearer to the coast and visiting it more often are associated with better self-reported general health. These results suggest that coastal access may be a viable and generalized route to promote public health across Europe and Australia. However, the relationships are not strongest among individuals with low household incomes, thereby challenging widespread assumptions of equigenesis that access to coastal environments can buffer income-related health inequalities.