I always wear a size 8.5 or 9, and this 8.5 was too large. My heel lifted out as I walked. I do have a narrow foot.

But, the sandal is really cute and comfortable so I went down to a size 8 (which I haven't worn since I was a teenager!) and it fits perfectly.

The blue is really pretty and versatile, so I recommend these highly. Just go down at least half the size if you have a narrow foot.