Cancun's hotel zone marina dispatches more than thirty catamarans each afternoon between three and five o'clock, each chasing the same westward horizon where the Caribbean meets the Yucatán shelf. The tradition began in the early nineteen-nineties when a handful of sailing operators realized that tourists would pay a premium to watch the sun drop behind Isla Mujeres with a rum punch in hand. By two thousand and ten the format had crystallized into the open-bar catamaran cruise, a hybrid of snorkeling excursion and floating cocktail party that now moves close to half a million passengers annually. The routes follow a predictable arc. Departures from Boulevard Kukulcán swing north past Punta Cancún, then cut northwest toward the shallow reefs off Isla Mujeres' southern coast. Most operators anchor for forty minutes of snorkeling over elkhorn coral beds, then motor to Playa Norte or a private beach club for a second stop. The return leg is timed to intercept the sunset between six-fifteen and six-forty-five, when the boat pivots west and the crew cranks the sound system. Open bars vary by operator but typically pour domestic beer, white rum, tequila blanco, vodka, and a rotating selection of tropical mixers. Premium sailings add mezcal and imported spirits. The Caribbean horizon here is unobstructed for thirty kilometers, a flat seam between ultramarine water and a sky that shifts from cerulean to tangerine in the span of twelve minutes. On clear evenings the sun compresses into an oblate sphere as it nears the waterline, a trick of atmospheric refraction that sailors call the Novaya Zemlya effect. The light turns molten orange, then rust, then a deep arterial red before the rim slips under. Photographers favor the minutes immediately after sunset when the western sky holds a gradient of violet and burnt sienna and the first stars emerge over the mainland. Sunset booze cruise Cancun operators compete on music selection, bartender showmanship, and the quality of snorkeling gear. Hip-hop party boats skew younger and louder; catamaran sailings targeting couples over thirty keep the volume lower and the deck less crowded. Adults-only departures eliminate families and spring-break groups, a distinction that matters during peak season when some boats carry a hundred passengers. The federal dock tax of twenty dollars per person, paid at the marina before boarding, is standard across all operators and non-negotiable.