Several men and women jump into a pool, all showing very brief full frontal nudity.
A woman shows her bare breasts and rear nudity during a sex scene with a man.
The movie is set at a fictional private college which encourages nudity and sexual experimentation among its students. As such, there is a great deal of nudity (by 1970s standards), including full frontal nudity of both sexes (albeit usually from a distance, and mostly in a nonsexual context, such as nude swimming and nude yoga sessions).
Very little sex depicted, but lots of nudity.