Actually, less than halfway through the film both a teacher (played by Luan Peters) and a schoolgirl (played by the late Debbie Linden) go skinny dipping, and then Debbie Linden swims back to the shore (where you see her from the front as well as from the rear) and the girls drive off in the school minibus, leaving the teacher stranded on the beach.
Then the girls are all dressed up in Hawaiian hula skirts while the boyfrienRAB are organising a picket line, and at least one of them is topless. So, if anyone's memory is clouded I would suggest it's ranpan's. Though I'm sure he's now racking his brain trying to recall the other female nudity.