There are many naturist/ clothing optional beaches on Mallorca.
The best, I think, is Es Trenc, in the south of the Island and a great one through  Magaluff, El Toro, I think it's called, small sheltered a great beach bar nearby plenty of sun beds and parasols. Mike

I can recommend Cala Mesquida in the North East Corner of the Island . It is part of a purpose built complex , but the far end is naturist , lovely setting and close to amenities . There is a nature reserve behind if you fancy a wander .

Es Trenc is the most well known and enormous. Arguably the best on Majorca.
The one MikecC mentions I think is also called Platja Mago. It is about 100 m long and is overlooked by the bar. So, if you don't mind that, then it is OK.