An open shoe, such as a slipper, sandal and the like, comprising a sole with which an insole and an upper are associated. The insole has part of its edges engaged in a corresponding recess, which is provided as an undercut on the upper perimetric side wall of the sole and is formed by an inward rim, which is perimetric and has, for each side of the sole, a discontinuity for guiding insertion of the edges of the insole in the inward lip. The discontinuities are located at at least part of the regions of the side wall where the upper connects.