A shoe system including a shoe upper with a bottom side having an aperture extending to a cavity. The shoe system also includes a selectively removable outsole which includes a bottom for contacting the ground, and a top for engaging with the bottom of the shoe upper. The top side of the outsole further includes a projection which is sized and shaped to extend through the aperture and into the cavity when the outsole is in a first orientation, which is misaligned with respect to the shoe upper. The projection is also sized and shaped to fit within the cavity but no longer back through the aperture when the outsole is in a second orientation, which is aligned with respect to the shoe upper. In the second orientation, the projection within said cavity prevents disengagement of the outsole from the shoe upper.