The three-degree of freedom fin apparatus and method described herein is for use on a watercraft (such as a surfboard) and allows adjustment of up to three degrees of freedom, including a translational degree of freedom along a longitudinal axis of the fin structure in the fore and aft direction (longitudinal translation or pitch), a first rotational degree of freedom about the longitudinal axis (roll), and a second rotational degree of freedom about a vertical axis centered at a point on the fin (yaw). Pitch adjustment is made by sliding a base plate and fin assembly along the longitudinal axis. Yaw adjustment is made by moving a front portion of the fin assembly about a yaw pivot point and the rear portion along a yaw track in the base plate. A roll adjustment is made by rotating a fin unit of the fin assembly about the longitudinal axis.