During the COVID-19 (coronavirus disease of 2019) pandemic, researchers havebeen seeking low-cost and accessible means of providing protection from its harms,particularly for at-risk individuals such as those with cardiovascular disease, diabetes andobesity. One possible way is via safe sun exposure, and/or dietary supplementation withinduced beneficial mediators (e.g., vitamin D). In this narrative review, we provide rationaleand updated evidence on the potential benefits and harms of sun exposure and ultraviolet(UV) light that may impact COVID-19. We review recent studies that provide new evidencefor any benefits (or otherwise) of UV light, sun exposure, andthe induced mediators,vitamin D and nitric oxide, and their potential to modulate morbidity and mortalityinduced by infection with SARS-CoV-2 (severe acute respiratory disease coronavirus-2).We identified substantial interest in this research area, with many commentaries andreviews already published; however, most of these have focused on vitamin D, with lessconsideration of UV light (or sun exposure) or other mediators such as nitric oxide. Datacollected to-date suggest that ambient levels of both UVA and UVB may be beneficialfor reducing severity or mortality due to COVID-19, with some inconsistent findings.Currently unresolved are the nature of the associations between blood 25-hydroxyvitaminD and COVID-19 measures, with more prospective data needed that better considerlifestyle factors, such as physical activity and personal sun exposure levels. Anothershort-coming has been a lack of measurement of sun exposure,and its potentialto influence COVID-19 outcomes. We also discuss possible mechanisms by whichsun exposure, UV light and induced mediators could affect COVID-19 morbidity andmortality, by focusing on likely effects on viral pathogenesis, immunity and inflammation,and potential cardiometabolic protective mechanisms. Finally, we explore potentialissues including the impacts of exposure to high dose UV radiation on COVID-19 andvaccination, and effective and safe doses for vitamin D supplementation.