I have had many pairs of flip flops over the years...Quicksilver, Teva, Crocs etc.  I was turned on to these Olukai sandals at a surf shop in Delmar, Ca by a rep there.  He told me that these sandals are one of the few that actually have some arch support.  Boy, was he right.  They are by far the most comfortable sandals I have ever owned and better, they never leak color onto your feet after long wear like the others I have owned.  I just purchased this second pair from Amazon at a much better price.

I wear a 9 shoe and the 10 is a perfect fit.