Various features for improving the performance of prosthetic sport feet are provided. Prosthetic sport feet according to the present disclosure can be designed to improve performance in board sport activities, for example, surfing, windsurfing, kitesurfing, wakeboarding, skateboarding, snowboarding, skiing, and the like. A prosthetic board sports foot can have a wide profile and large area for contacting the board or ground to improve stability. The board sports foot can include a traction sole to reduce slippage on the board. The board sports foot can also include an attachment member for attaching the foot to a user's residual limb or another prosthetic component. The attachment member can include a tendon designed to allow for flexibility over an initial short range of movement. The tendon can be interchangeable, and tendons having various stiffnesses can be provided.