Sian Ka'an & the Punta Allen Peninsula 

Just past Tulum's last cabaña hotel is the entrance arch to the vast (526,000-hectare/1.3-million-acre) Sian Ka'an Biosphere Reserve. This inexpressibly beautiful tract of wild land is the domain of howler monkeys, ocelots, crocodiles, jaguars, tapirs, sea turtles, and thousands of species of plants. The Mexican government created this reserve in 1986; the following year, the United Nations declared it a World Heritage Site. Sian Ka'an protects 10% of Quintana Roo's land mass, including almost one-third of the Caribbean coastline, from development. Another 319,000 hectares (788,300 acres) of land was added to the reserve in 2010.

The entrance to the Punta Allen Peninsula, a small portion of the reserve, is one of two main entrances to the reserve; the other is from the community of Muyil off Hwy. 307 south of Tulum, where you take a boat down canals built by the Maya to the Boca Paila lagoon.

Legends still swirl about the 4 hours it takes to drive the 50km (31 miles) over potholes, ruts, and rivulets to the town of Punta Allen at road's end. In fact, the road has been much improved, though it is still dirt, still pockmarked to varying degrees, and subject to weather-related conditions. Guards at the entrance gate are fond of declaring it's now a 1-hour trip, and no doubt that's true for the locals who sailed past me in my rented compact sedan. Driving cautiously after a stretch of rainy weather, it took me a little less than 2 hours. Those driving four-wheelers or other robust vehicles should plan to spend about 1 1/2 hours on the road.

If you don't fancy yourself a road warrior, you can drive through the entrance arch in Tulum (entry 25 pesos per person) and continue south about 4km (2 1/2 miles) to where a beach comes into view, pull over, and spread out your beach towel.

The Punta Allen Peninsula -- As you drive the skinny peninsula, which separates the Boca Paila Lagoon from the sea, you'll find no trails leading into the jungle and much of the coastal side of the road is fenced off. But you can swim or snorkel off the beaches that come into view. Guided tours are the only way to see most of the reserve. Otherwise, there is no practical way to visit Sian Ka'an except by car.

The Road to Punta Allen -- About 11km (6.8 miles) past the arch, you'll come to the Boca Paila Fishing Lodge (www.bocapaila.com). Not for the general traveler, it specializes in weeklong, all-inclusive packages for fly-fishers. The peninsula is so narrow here that you see the Boca Paila lagoon on one side and the sea on the other. In another 3km (1 3/4 miles), you will be flooded by false hope when you reach a smooth, concrete roadway -- this is the foot of the Boca Paila Bridge, which spans the inlet between the ocean and the lagoon, and the pavement disappears as quickly as it appeared. You'll often see people fishing off the sides. This is a good place to stop and stretch your legs while taking in ethereal water views from either side.

After the bridge, it's mostly deserted coastline until you get to Punta Allen. About 8km (5 miles) before you do, you'll come to Rancho Sol Caribe (www.solcaribe-mexico.com), with four comfortable cabañas and the stunning beach it has all to itself.

Punta Allen -- Punta Allen, the peninsula's only town, is a lobster fishing village on a palm-studded beach perched between Ascension Bay and the Caribbean Sea. About 100 families survive by lobster fishing and, increasingly, tourism; many of the young men now are expert fly-fishing guides.

Isolated and rustic, this is very much the end of the road. The town has a lobster cooperative, a few sand streets with modest homes, and a lighthouse. The generator, when it's working, comes on for a few hours in the morning and a few more at night. Your cellphone won't work here, and no one takes credit cards. Without the help of a friendly local, it's a challenge to figure out when any of the businesses are open.

This is slowly beginning to change. The few lodges that bravely set up shop here 10 or 15 years ago have acquired some upstart young neighbors, and 80 more guest rooms have been approved (no telling how long they might take to materialize). For now, unless you're a fishing enthusiast, there's not a lot to do in Punta Allen except kick back, snorkel a little, and eat your fill of fresh seafood.

En Route to the Lower Caribbean Coast -- About 25km (16 miles) south of Tulum on Hwy. 307, a sign points to the small but interesting ruins of Muyil (take bug spray), on the western edge of Sian Ka'an. The principal ruins are a small group of buildings and a plaza dominated by the Castillo. It's one of the Caribbean coast's taller structures but is more interesting for the unique, solid round masonry turret at the top. A Maya canal enters the biosphere reserve and empties into a lake; more canals then continue to the saltwater estuary of Boca Paila. The local community offers a boat ride through these canals and lakes. The 3 1/2-hour tour includes viewing some otherwise inaccessible ruins, snorkeling the canal, and floating in its current.

Felipe Carrillo Puerto (pop. 60,000) is the first large town on the road to Chetumal. The town was a rebel stronghold during the War of the Castes and home to the millenarian cult of the "Talking Cross." A sizable community of believers still practices its own brand of religion and commands the town's respect. Of primary interest to travelers, however, are Carrillo Puerto's two gas stations, a market, a bus terminal, and a bank next to the gas station in the center of town, which has an ATM. From Carrillo Puerto, Hwy. 184 goes into the peninsula's interior and eventually to Mérida, making it a turning point on the "short circuit" of the Yucatán Peninsula.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.