Background Although outdoor water sport activities are gaining increasing attention for their therapeutic potential in the social and care management of populations with chronic diseases, these practices are currently underutilised. Moreover, the available body of literature on the topic has not been critically and comprehensively assessed yet. Aims (1) To appraise the health effects of outdoor water sport activities for chronic disease populations; (2) to preliminarily assess the potential size and scope of the available research literature for this emerging field and identify potential gaps and avenues of development. Methods A literature search was performed scanning PubMed (including MEDLINE), Physiotherapy Evidence Database (PEDro) and Scopus from inception to December 2021. A scoping review was carried out by appraising all the available evidence on outdoor water sport interventions specifically designed for therapeutic purposes for individuals with chronic disease. The quality score of each study was calculated with the Tool for the assEssment of Study qualiTy and reporting in Exercise (TESTEX) tool. Results Fifteen studies (five RCTs, seven non-RCTs and three CTs with healthy subjects as controls) met the inclusion criteria and were assessed. Among the studies selected, two focused on canoa kayak, one on stand-up paddle, two on surfing, two on sailing activity, and eight on dragon boat padding. The median TESTEX score for study quality and reporting was 6/15, i.e., “very low” (range 5–8). Based on the qualitative analysis, the few individual studies that could be included reported generally positive results, ranging from improvements in antioxidant action and cardiovascular function for dragon boating, to beneficial effects on balance, postural control, and flexibility for on-water paddle board activities. Overall, outdoor water sport interventions were associated to higher rates of adherence than conventional trainings. Conclusions Very low to low quality evidence from a limited set of pilot studies seems to suggest beneficial effects of outdoor water sports for chronic disease populations. However, such preliminary findings need to be replicated through large, high-quality RCTs to be conducted in target populations. Avenues of development, scoping directions and translational perspectives for this specific research field are proposed and discussed.