Playa Jandía is a beach near the south tip of the island. Flanked by massive sand dunes, it is a very shallow, gradual beach. The tide can swallow 150m of coast as it rises and falls. The dunes are allegedly a nature preserve, but that doesn't stop people from climbing up them. I didn't do it because the signs said not to, but it was tempting.
Instead I enjoyed a long walk along this beach to the cliff at the far end. I actually started out by picking up some plastic that washed ashore and looking for a trash can, but it turned into a nice hour-long walk. Great beach for a casual stroll!