Swim Shoes Recs?

We joined a pool this weekend and Coop's feet are TORN UP from walking around the baby pool.  He looks like his feet were attacked by a very mean cat.  The smallest swim shoe I can find in a store is a 5 and he's barely a 4.  I found some flimsy baby type foot covers, but with hima actually walking they won't work.

Anyone know of any very small water shoes for walkers?