Hia Shellz, we have only stayed at the Marhaba complex Sousse, and never had a problem with the beach being over crowded as it stretches right the was long, we aslo went in August, we did get hassled a bit, but a polite No thank you seemed to work, although some guys were a bit more persistant than others.
I too only really know the beaches round Sousse and have never been in the height of summer so can't give you any more information than Roo but, as she says, the beaches are long and lovely so you shouldn't have a problem in finding a nice space. Perhaps someone else on here can let you know about the Hammamet area.
hello..best beaches are in sousse...that's why they always be crowd and empty...so if you want to swim alone i advise you to visit MAHDIA,it is not far from sousse or BIZERT in the NORTH..but i tink best place for swiming or tourism is TABARKA...you will spend nice holiday there by its natural sight...don't hesitate you can visit it via internet before coming..I WISH YOU FIND THE BEST PLACE tup