I got a medium width, but I couldn't cinch them up enough to keep my foot from sliding around (actually slipping off the sole, making me worried that I might twist my ankle.)  Since there's nothing much to hold the foot on (and that's a given with this type of sandal), I walked around only a little before deciding this wouldn't work for me.  If you've more flesh on your foot, it might work, but skinny feet (not wide, but bony) it's risky.