The so-called Ruta de los Cenotes is a road that runs inland from Puerto Morelos, past several swimming holes and caves (all open daily 10am–5pm). Look for the turn inland just south of the main Puerto Morelos intersection, marked by a large cement arch. Dive shops in Puerto Morelos also run snorkelling and diving trips out here.
Several spots are for group tours from Cancún, but a couple are open for independent travellers. The best is Cenote Las Mojarras (998 147 0168, facebook.com/ParqueCenoteLasMojarras; M$250), at km 12.5, a big open pool with a zipline. Entry fees can be lower if you’re only staying a couple of hours, but with nature trails, lunch cooked over a wood fire and an enthusiastic manager who knows everything about the local plants, you can spend all day here; you can even camp, with prior reservations.
Several kilometres further is Siete Bocas (M$100), a water-filled cave with seven points of entry, best for divers, as there’s not much natural light. At km 17.5, Verde Lucero (M$60) is a pretty, rustic-feeling pool with only basic facilities – some bathrooms and basic snacks.