I wear an 8.5 but my feet are a little wide so occasionally size up to a 9.  In this case I ordered a 9 and true to the reviews struggled to get my heels through the narrow ankles.  Finally I put some lotion on and got one foot in.  The boot fit very nicely then, not too narrow. They appear to be continuous with no seams for water to get in, but the tall, narrow heel doesn't make them ideal for play.  Then I almost had a panic attack trying to get it back off.  I ordered another Kamik style in a 10, first time in my life, and they fit like my size 9 running shoes.