Stretching Rubber Shoes

Put plastic bags inside the shoes, fill the bags with water and then freeze the whole thing, this seems to stretch the shoes enough to wear.

Rubber is difficult to stretch permanently-you could take the shoes to a shoe repair store and ask what can be done. I've had some very good results from my favorite shoe repair person who helps me with shoe modifications for my old ballet feet. For a less aggressive approach: If you wear socks with them, try wearing two pair or thicker and much thicker socks.