Background: Stand-up paddle boarding (SUP) is a recreational activity and sport that has grown exponentially, with participation increasing from 1.1 million in 2010 to 2.8 million in 2014 in the United States alone. Despite this growth in participation, SUP remains underresearched with regard to injury epidemiology. Purpose: To investigate injury epidemiology (severity, location, type, mechanism) in SUP. Study Design: Descriptive epidemiology study. Methods: An open-source online survey was administered to active SUP participants internationally. The survey captured information relevant to demographics, participation, and injury history over the past 12 months. Results: Of 240 participants included in the data analysis, 67.1% were males, and 54.6% were involved in competition. Participants spent a mean 192.6 ± 179.5 hours participating in SUP per year, most commonly for fun and fitness (43.3%) at the beach or bay (63.0%). A total of 95 participants had sustained at least 1 injury. A total of 161 injuries were recorded, resulting in an injury rate of 3.63 (95% CI, 3.04-4.16) per 1000 hours of SUP. The shoulder/upper arm was the most frequently injured body location, accounting for 32.9% of all injuries, followed by the lower back (14.3%) and the elbow/forearm (11.8%). The most common injury types were to muscle/tendon (50.4%), joint/ligament (22.6%), and skin (14.2%). Endurance paddling was the most frequently reported mechanism of injury (34.5%), followed by contact with a paddler’s own board (20.1%) and sprint paddling (9.3%). Key risk factors for sustaining an injury were age >46 years, competitive status, and participating for >4.8 hours/week, as well as using SUP for racing. Conclusion: This is the first study to report injury epidemiology for SUP. It is evident that both sexes participate in SUP for fun, fitness, and competition. With regard to injuries, the shoulder, lower back, and elbow are the most injury prone; older age, competitive status, and longer hours of participation all influenced the chance of injury. Findings from this study provide the foundation for injury prevention strategies.