The next bay South from San Stefanos, already mentioned, is the quiet beach at Arillas. It's long and narrow with naturist stretches at each end. The North end is backed by high cliffs which are eroding and dangerous in places but the condition of the beach and its access changes seasonally due to tide and wind. It's still a great place with clean shallow water. There's some 'green mud' in the cliff to slap on for its refreshing/healthy properties, alledgedly! Good for a giggle, anyway!
The South beach is below a high bank and quite safe.
There's a Brit community there and very active on the website arillas.com. 'Thompsons' feature it but there is plenty of other accommodation available.
Walks to San Stefanos , Afionas and Agios Georgios via the coastal 'bridle paths' are highly recommended if you are OK with some uphill work. Car hire is available right there.
It's very laid-back, friendly and excellent eating places. If that's your idea of a naturist holiday you won't be disappointed!

P.S. There are amazing sunsets because it's West-facing, the best kind of beach in my opinion!