I really appreciate when people ask questions about my products because then I know what I'm forgetting to tell you! I spent a long time looking for the right material for the soles of my shoes. This is a rubberized neoprene which has a nice, rubbery texture on the sole side and the inside feels like fabric. It's flexible like fabric and has about the thickness of denim, so the wearer feels the floor under their feet. Kids benefit from a flexible sole and adequate space especially as their feet are developing in the first several years of life.