What's the must-see thing in Cozumel?

The reef is the reason Cozumel exists as a destination. Not the duty-free shops along Avenida Rafael Melgar, not the cruise terminal where 3 to 4 million passengers step off each year. The Arrecifes de Cozumel National Park, established in 1996, protects the coral system running along the island's southwest shore. You smell diesel and brine at the San Miguel marina before the boat clears the harbour wall. Ten minutes out, the water shifts from milky green to a blue so clear you can see parrotfish working the coral 8 metres below. Palancar reef, about 1.5 kilometres offshore, is the one most boats visit. Colombia reef sits farther south and tends to draw fewer boats. Cruise-ship passengers should book at a San Miguel marina operator instead of the ship's excursion desk, which marks up the identical trip by 40 to 60 percent.

San Gervasio sits about 15 kilometres east of San Miguel, off the Carretera Transversal. This was a pilgrimage centre for Ix Chel, the Maya goddess of fertility and medicine. Women traveled here from across the Yucatan Peninsula for centuries before Spanish contact. The structures are smaller than Tulum or Chichen Itza, and the carvings have weathered more heavily. But the site rarely fills with tour groups, and the jungle canopy overhead keeps temperatures a few degrees below the 32°C you feel on the coast. The full walking circuit takes about 90 minutes. Entry currently costs around 270 MXN. Bring water for the 400-metre gravel path from the parking lot to the first structure, which runs in full sun. The midday humidity, around 60 percent, makes that short stretch feel twice as long.

Punta Sur Ecological Park covers the island's southern tip, about 27 kilometres from San Miguel. The Faro Celarain lighthouse gives the widest view on Cozumel, and the coastal lagoon below holds American crocodiles that doze on the muddy banks in late morning heat. You hear the wind pick up as you walk toward the southern shore. The surf hits harder than the sheltered west coast, and the salt spray carries farther than you'd expect. Entry runs around 500 MXN. The park closes at 4pm, so an early afternoon arrival works better than trying to squeeze it after a morning reef trip. For a proper swim on the wild side of the island, Chen Rio beach sits on the east coast about 20 minutes north by car. The waves at Chen Rio face the open Caribbean year-round.

On Cozumel, the right sequence matters more than the right list. Day one, take a morning snorkeling trip to Palancar while the water is calmest. Day two, taxi to San Gervasio when the site is cool, then drive the coastal road south to Punta Sur for the afternoon. If you're arriving by cruise ship with 6 to 8 hours, skip the Avenida Rafael Melgar shops and head straight to the marina. Taxi fares on Cozumel aren't metered. The ride from the cruise terminal to San Miguel's central plaza costs about 150 MXN, and a round-trip to San Gervasio with a 90-minute wait runs roughly 500 MXN. The island measures about 48 kilometres long by 16 wide, so nothing is more than 40 minutes away.