We have gone at the end of August the last few years staying in SSR, AKV (Jambo), and BCV. Obviously the pools are quite popular that time of year since it is 90+ degrees every day, but we haven't found any of them to be overly crowded. I guess if I had to choose a least crowded one of the three it would be Jambo's pool. That being said , SAB wasn't too bad last year when we were there either. We don't spend tons of time in the pool though. When we swim it is usually mid day between lunch and dinner.