I bought a size 9 in these and a size 9 in the Crocs Meleen and Hurache sandals.  My meleen sandals fit better than these.  The cleo II has about a 25.5&#34; insole, and 26.5&#34; length total.  The crocs meleen sandal has a 26.5&#34; insole, and 26.5&#34; length total.  The Hurache sandal has a 26.5&#34; insole and 27&#34; length total.  I wish crocs would standardize their sizes better, because a size 9 in three different sandals is totally different. I debated for a long time whether to buy a 9 or 10.  When I wear the strap forward on these, it's pretty comfortable, but they can slip off if you have a narrow foot.  When I wore the strap in the back it sometimes slipped down off my heel, which made it a little hard to walk sometimes.  Although I feel like it's a little small, I don't think that a size 10 would have fit well, especially since the strap falls off my heel when worn in the back.  These sandals do look nicer than the meleen though, and they are more comfortable for walking than the Hurache sandals. I would buy them again, but probably in the next size up.  I am decently satisfied with these shoes. I think if you normally wear a 9-10, you probably would feel fine in the 9.  As far as comfort, there is no arch support in these sandals, unlike some other crocs.  Also, when I've been walking on sand, and sand gets in the sandals it starts to rub my skin on my toes too much.  It could be just me though. Other than getting too sandy, these shoes are pretty average in comfort (I have worn them all day, but still have a little knee pain at the end of the day)