Haulover Park offers a clothing optional area at it's northern end. It is sanctioned by the state and is visited by people of all shapes sizes ages countries and ethnicities. It is only about 15-20 mins north of the hotels in Miami Beach (where you can also go topless and the crowd is usually younger). There's a food concession, volleyball court, bathrooms, showers, parking for a small fee, security, lifeguards, chairs and umbrellas for rent, a beautiful beach and great ocean. The northern end of the beach tends to attract gay men. PDA's aren't tolerated but are not unheard of. It can get crowded on the weekends too though I imagine Sept would be less so. Of course the weather is usually awesome except during a hurricane.
