I'm surprised no one has mentioned Orient Beach on St. Martin. We go every year and stay most of the time at Club Orient. They have a quarter mile long clothing optional beach with great sand and gentle wave action. Most people on the beach are nude. One downside is clothed gawkers when there's a cruise ship (or four or five) in port. There are many nude beaches on the Mediterranean but one should be aware that many are rocky or pebbly rather than sandy.
For the Europeans on this site I would recommend Maspalomas in Gran Canaria. It's a long beach and easily accessible from the main resort. It's OK if you don't mind the constant stream of textiles walking along the edge of the sea. For more privacy venture into the vast area of dunes, this also provides some shelter from the wind which can blow the sand on the beach. I've been in November and February but the temperature is good so great for being nude.
Hanlan's Point in Toronto, so close to home.Cayo Largo in Cuba, a great beach to walk nude forever.
I went to Hanlan's Point last year when I visited Toronto. Was very nice and had a nice view of the Toronto Skyline.
In Portland, OR I go to Collins Beach which is packed on the weekends.