San Juan Bay has carried trade galleons, privateers, and naval fleets for five centuries, but its most reliable traffic today arrives between 5 and 7 p.m., when catamarans and sloops slip from their berths to frame the walled city against the western sky. The bay's protected waters — sheltered by the Condado peninsula to the east and the Atlantic swell by a narrow harbor mouth — create an amphitheater for sunset, with El Morro's six-tiered ramparts and the pastel facades of colonial Old San Juan stacked vertically along the shore. The bay itself is a working waterway: container ships queue at the Pan American Dock, cruise terminals flank Pier 3, and the Coast Guard station occupies the northern arm, yet the evening light softens infrastructure into silhouette, rendering the scene as it might have appeared to Spanish lookouts in 1625. Sunset sails in San Juan Bay trace a route pioneered by 16th-century supply vessels threading the Boquerón channel, where tidal currents from the Atlantic meet the calmer inner harbor. Modern operators favor shallow-draft catamarans and monohulls that can navigate close to the colonial seawall without disturbing the cargo lanes. Departure times shift with the solar calendar — earlier in winter, later in summer — but operators cluster bookings around the golden hour window to maximize the interplay of low-angle light on limestone fortifications. The bay's orientation, open to the west, ensures unobstructed views of the sun descending into the Caribbean, with no offshore islands or headlands to interrupt the horizon line. The ritual of the evening cruise emerged in the late 20th century as San Juan pivoted from military port to tourism hub, but the bay itself remains anchored by structures predating that shift: Castillo San Felipe del Morro, completed in 1589; La Fortaleza, the oldest governor's residence in continuous use in the Americas since 1540; and the colonial grid climbing uphill from the water. Operators maintain strict adherence to Coast Guard navigation zones, keeping recreational vessels clear of commercial shipping channels and respecting no-wake zones near the historic waterfront. The result is a choreographed procession — vessels depart at staggered intervals, loop west toward the harbor mouth, then arc back east along the city wall as twilight deepens, timing their return to coincide with the first lights appearing in the old town's window grilles and lampposts.