Los Charcones is a ragged stretch of volcanic coast west of Playa Blanca where the sea has cut natural pools into the black rock. In calm conditions the contrast is gorgeous: pale foam, dark lava shelves, and clear water held in basins of different sizes and depths.
Treat it as a viewpoint first and a swimming spot only if the sea is genuinely settled. Access is rough, there are no facilities or lifeguards, and Atlantic swell can turn the pools from photogenic to dangerous very quickly. Good shoes and conservative judgement matter more here than a towel.