I know I may be biased but after visiting:
I have finally decided that the most gorgeous beach I have seen while here is El Cotillo in Fuerteventura. The beach has several lagoons, and beautiful white sands. However there is also volcanic rock amidst the sands and therefore there are many cool tide pools, fish, shells and interesting things to play around with and look at. The waves are huge and crashing and the color of the water is a crystal clear blue-green, reminiscent of the Caribbean.
This beach is off the beaten path, however it´s not deserted. It´s not a nude beach but you will see nudists here, so if that creeps you out, this beach is not for you. Also if you enjoy finding hermit crabs, seeing fish…it´s got marine life too!
Make sure to drive up to the main town of El Cotillo to enjoy some delicious seafood and wine just in time for the sunset. I recommend the restaurant, La Vaca Azul, with delicious seafood and amazing views.
Finally, La Vaca Azul!