Our group of five divers gathers near the entrance at 80 feet, testing lights and summoning courage before squeezing into the coral-encrusted chasm called Devil's Throat.
We head straight down a twisting chute that leads to The Cathedral, a cavernous room where several other shadowy passageways meet.
Pursuing the divemaster through another steeply angled tunnel, the beam from my light dances across the sloping walls - freezing on an ivory sponge eerily growing in the shape of a cross.
The adrenaline-rich maze ends at a depth of 120 feet, where we are greeted by blue water bathed in brilliant sunlight. Sixty feet below, a big barracuda watches as two stingrays fly gracefully across a sandy plain that reaches to infinity.
Surfacing 20 minutes later in rolling swells off the southern tip of Cozumel, I realize it's unforgettable underwater experiences like this that lure loyal divers back to Mexico's largest Caribbean island.
During a week spent exploring the far ends of the island, I also learned that there is far more to Cozumel diving than deep walls and thrilling swim-throughs. And as a returning visitor, I was again reminded that there is far more to Cozumel than just diving.
None of my companions on the boat expected much from the afternoon's second dive. They figured that no shallow site could compare to the giddy rush we had felt plunging through Devil's Throat. Their attitudes also were dampened by the reality that the sun was starting to sink and the wind was beginning to howl. But everyone's outlook brightened after we dropped into the clear water offshore Reef Club Isla Cozumel. A steady current was guiding us over a lush coral garden featuring an impressive array of tropical marine life that grew increasingly active as sunset approached.
With dense schools of jacks and grunts hovering above, a small squadron of parrotfish munched on the coral outcroppings. At the end of the dive, as daylight began to ebb, we briefly followed a 5-foot nurse shark heading out for happy hour.
Most of the diving in Cozumel takes place off the southwestern corner of the island where reefs and marine life thrive in 80-degree water stirred by brisk currents. This underwater breeze, which is partly the result of fluid dynamics created by the Abyssal Trench that extends south to Belize, allows divers to glide effortlessly past a stunning variety of submerged sites. Visibility on many dives often exceeds 150 feet.
Among divers, the island's best-known attraction is Palancar Reef - you'll recognize it by the flotilla of boats that converge there each morning. But don't worry about the crowds; Cozumel's signature reef extends for more than three miles and includes several diverse dive sites - leaving plenty of room for everyone.
Like many newcomers, I sampled this area on my first visit to Cozumel, which came during a whirlwind tour of the Yucatan Peninsula in 1994. It was also the first place that I returned to on my recent trip.
At Palancar Caves, we drifted in and out of picturesque canyons filled with massive brain corals and wiggling giant anemones. Three black-tip sharks lurked beyond the edge of the deep wall as a gentle green turtle meandered by during our safety stop.
The diving was incredible - just like I remembered it.
One of my days in Cozumel was supposed to be devoted to diving on a Mexican naval vessel that was intentionally scuttled last year. Large holes have been cut in the ship, which is also equipped with penetration lines. The new wreck has received rave reviews, and I was eager to see it for myself.
But the trip was cancelled because of a lack of divers. Fuming at a lost opportunity, I decided a change in scenery was needed. Soon I was sitting in a taxi listening to the cheerful driver brag about the money that his son is raking in as a fisherman in Miami.
The taxi dropped me off in San Miguel, Cozumel's only town. Tourists were streaming by the restaurants, bars and shops on the main oceanfront avenue.
To escape the crowds, I walked a couple blocks inland to the town's central plaza. Salsa music poured from loudspeakers on one side of the square where local children were exchanging holiday gifts. Later, they enthusiastically serenaded patrons at nearby restaurants.
Wandering around the back streets of town, I marveled at how this once sleepy fishing village has transformed itself into a bustling tourism center without sacrificing its authentic Mexican charm.
An Evolving Dive Destination
San Miguel and the rest of Cozumel certainly have seen some major changes in recent decades. That's what happens when a paradise is found - first by scuba divers and later by a fleet of towering cruise ships.
In terms of diving, Jacques Cousteau put Cozumel on the map when he told the world about this aquatic wonderland after his first visit in 1961. The island quickly became a beacon for adventurous travelers who dived from small local fishing boats and stayed in ridiculously cheap hotel rooms.
Cozumel has evolved since those early days into a world-class diving destination with more than 100 dive shops and boats that are as professional and modern as any found throughout the Caribbean.
Though it remains a convenient, safe and relatively affordable getaway for Americans, the unbelievable bargains Cozumel was once known for have vanished. Today many divers opt for the luxurious all-inclusive oceanfront resorts north and south of San Miguel. I stayed at the Hotel La Ceiba, a moderately priced resort that has long been a favorite of returning divers. Less expensive accommodations still can be found in town.
Yet the main reason that thousands of divers from Colorado, Illinois, Texas and other states return year after year is the superb condition of Cozumel's underwater landscape. This is largely due to the island's ever-present currents.
These currents keep the corals and sponges healthy by providing a plentiful supply of nutrients. They also flush away sediments that would otherwise cloud the water column. And the constant water flow helps prevent novice divers from bumping into fragile reefs.
In addition to the ideal conditions, the strong emphasis that the island's dive professionals put on marine conservation cannot be overlooked. These dive shop owners, boat captains and dive masters deserve credit for supporting and even spearheading efforts to create a national marine park to protect Cozumel's reefs.
Cruise ships cometh
Divers made their mark in Cozumel, but it's the cruise ships that have had the most recent impact.
More than 20 of these floating skyscrapers now call on the island each week, disgorging scores of passengers who invariably wind up at the town's centrally located slew of Americanized joints like the Hard Rock Cafe, Planet Hollywood and Pizza Hut.
Many of the cruise ship passengers and visiting divers from the U.S. experience their first brush with foreign culture while in Cozumel. But few of these travelers make the most of this opportunity by venturing beyond the oceanfront storefronts and main plaza.