Fin movement versatility in fishes is critical for avoiding predators, capturing prey, navigating complex environments, swimming efficiently at different speeds, and even properly positioning during mating. Many stingray species rely on both undulatory (wave-like) and oscillatory (flap-like) movements of their pectoral fins. The importance of these two fin motion patterns change in relation to multiple factors, such as lifestyle, environment, locomotory behavior, and swim speed. For this study, we focus on how wave and flap-like patterns change with swimming speed in Atlantic stingrays Hypsanus sabinus. Animals (20-30 cm disc width) were placed in a water tunnel and filmed swimming over a range of speeds (2 cm/s – 20 cm/s) using multiple high-speed cameras. The high-speed data were analyzed using proper orthogonal decomposition (POD) to decouple and identify dominant fin motions. The Atlantic stingrays exhibited multiple prominent POD fin modes, each with distinct frequencies and wavelengths. While stingrays relied heavily on undulatory fin motions throughout their speed range, the importance of oscillatory motions increased at higher swimming speeds, presumably to generate greater thrust via circulatory forces. Our data suggest that pectoral fin motions in Atlantic stingrays are multifaceted, with multiple POD modes comprising the total fin motion, and small changes in fin behavior can affect overall swimming performance.