The Cozumel Reefs National Marine Park protects 29,066 hectares of coral formations along the island's southwestern coast, designated in 1996 under federal decree to safeguard the second-largest barrier reef system in the Western Hemisphere. The park encompasses more than sixty named dive sites, but three reefs — Palancar, Colombia, and Paradise — anchor most recreational snorkeling itineraries due to their depth range of three to twelve meters and year-round clarity exceeding twenty-five meters during calm conditions. Palancar Reef alone stretches five kilometers and descends in terraced steps; its shallow fingers host elkhorn coral, brain coral, and vast colonies of sea fans that lean into the Yucatan Current. Colombia Reef, positioned farther south, presents vertical walls riddled with swim-throughs and crevices where spotted eagle rays and green sea turtles glide between ledges. Paradise Reef, the northernmost and shallowest of the trio, lies within ten minutes of the international pier and serves as the acclimation site for most half-day excursions. Cozumel's reef architecture owes its density to a geological quirk: the island sits atop a submerged limestone platform riddled with cenote-fed freshwater springs, creating nutrient upwellings that sustain coral polyps and filter-feeding invertebrates. By the mid-1990s, cruise ship anchoring and unregulated dive operators had damaged portions of Palancar's spur-and-groove formations; the federal marine park designation introduced mooring buoys, zoning restrictions, and the 225 MXN per-person conservation fee now collected at all authorized entry points. That fee funds patrol vessels and coral restoration projects managed by CONANP, the National Commission of Protected Natural Areas. A cozumel 3 reef snorkel by boat departs from the Puerta Maya or Punta Langosta piers between eight and noon, when wind speeds average below twelve knots and surface chop remains minimal. Operators use twenty-six to thirty-two-foot pangas equipped with VHF radios, oxygen kits, and twin outboards capable of covering the eleven-kilometer route to Palancar in under thirty minutes. Most itineraries allocate forty-five minutes per reef, with snorkelers entering the water from stern ladders and drifting along the reef crest while the boat shadows overhead. The marine park prohibits touching coral, feeding fish, or wearing chemical sunscreen; biodegradable alternatives and full-coverage rash guards are standard issue on compliant vessels.