A recurring trend in evidence scrutinised over the past few decades is that disease outbreaks will become more frequent, intense, and widespread on land and in water, due to climate change. Pathogens and the diseases they inflict represent a major constraint on seafood production and yield, and by extension, food security. The risk(s) for fish and shellfish from disease is a function of pathogen characteristics, biological species identity, and the ambient environmental conditions. A changing climate can adversely influence the host and environment, while augmenting pathogen characteristics simultaneously, thereby favouring disease outbreaks. Herein, we use a series of case studies covering some of the world’s most cultured aquatic species (e.g., salmonids, penaeid shrimp, oysters), and the pathogens (viral, fungal, bacterial, parasitic) that afflict them, to illustrate the magnitude of disease-related problems linked to climate change.