Efforts to improve the quality and quantity of seafarers in the Royal Navy and merchant service became a particular concern amidst the degeneration debates of late-Victorian Britain. Maritime reformers not only promoted fitness in adult sailors, but also particularly sought to improve health and physique of boy recruits in order to rear a new generation of healthy sailors. This article shows how both services experimented with tighter admission criteria and dietary and exercise reforms, and became early advocates of using metrical standards to exclude all but the fittest, healthiest boys from training opportunities. While the physical monitoring of boy recruits undoubtedly showed the value of early lifestyle interventions in fostering healthy development, the rising physical standards of British seafarers in this period was just as much the result of restrictive medical examinations as a commitment to welfare initiatives.