We went to the small bay "Playa del Mago", it was a nice beach for a few hours, but it's rather mixed than naturist beach. Unfortunately many people arrive and don't dress off, although they could just go to the previous or next bay.
You can take the bus 105 from Palma bus station (that goes via Palmanova and Magaluf) and get off at the last stop "Sol de Mallorca".
Then a steep road downhill, this bay is the 2nd bay if you come from the bus. The view from up is really nice blue. The sandy beach isn't big, so it can get crowded in case of good weather. Part of it is dirty from seagrass.
So, it was definitely not my favorite nudist beach, but as we didn't find any alternative that could be reached without a car, it was okay for a visit.