A surface walker for human beings consisting of a chassis holding four articulated, movable limbs for walking. Each limb rests on foot, ski or float. Chassis is topped with cushioned seat whereon user lies prone on chest and belly with access to limbs, which are activated with arms and legs. Chassis height and limb length are adjustable. User regulates walking gait, limb stride and motion frequency of limbs. Walker advances on land and water and diverse landscapes. Design incorporates optional computer-controlled power assistance for walker motion and use of mechanical hand for enhanced traction and anchoring effects.