A surf foil and an eFoil both use hydrofoil technology to lift the board above the water for a smoother, faster ride, but they differ in propulsion methods. A surf foil relies on wave energy and the rider's ability to pump the board, requiring no motor or power source. It's generally used in wave conditions and demands more skill and physical effort. On the other hand, an eFoil is equipped with an electric motor and battery, allowing riders to glide above the water without waves or paddling. This makes eFoils more versatile, offering a more controlled and accessible ride for various water conditions.