At the northern end of Montezuma is Playa Grande, a 3 km expanse of white sand. Walking another 4 km along the pristine coast brings you to the Cocalitos waterfall, where fresh water cascades off an escarpment into lava rock swimming pools and then into the ocean.
Instead of walking, you could also make the trip riding on horseback along the beach.
Midway to the Cocalitos waterfalls you can have a break for cold drinks in a small beach bar where tame coatis hang around. And if you are dreaming of a seamless sun tan you can dispense with your bathing suite in the adjacent secluded cove.