A ski boot frame that is attachable to a soft shell snow boot, for example a snowboard boot, for downhill skiing. The ski boot frame is constructed of multiple rigid materials to provide a user with proper support for downhill skiing. The ski boot frame further includes adjustable toe clip and heel clips for attachment to a standard downhill ski binding. The toe and heel clips are preferably adjustable to fit the frame to a plurality of sizes of ski bindings. The ski boot frame further includes a calf support that provides for a progressive forward resistance critical for downhill skiing.