The St. Lawrence narrows to less than a kilometre at Quebec City, and the French colonial port has exploited that geography since 1608. Samuel de Champlain chose the rocky promontory for its defensibility, but the river itself became the colony's artery — furs downstream, settlers and supplies upstream, and warships in both directions during the Seven Years' War. By the nineteenth century, timber barges jostled with transatlantic steamers at Quai Chouinard, the working wharf that now serves evening cruise operators. The St. Lawrence remains a working seaway — container ships bound for the Great Lakes pass within sight of Old Quebec's Lower Town — but after dark the industrial rhythm gives way to leisure traffic. Sunset cruises depart from the same quays that once loaded square timber for British shipyards. The river corridor frames the Citadel, the ramparts lit in amber, and the Château Frontenac silhouette against the cliff face. The timing matters: twilight lasts longer in June and July, compressed in September and October when autumn colour migrates down the Laurentian valleys. Evening departures range from sightseeing loops to cocktail formats with onboard DJs, the latter targeting a younger demographic drawn to Old Port nightlife. The boat tour infrastructure clusters at the Dalhousie Street terminal, a five-minute walk from Place Royale. Operators coordinate schedules to avoid congestion at the single embarkment pier. Zodiac-style inflatables offer open-air speed runs to Montmorency Falls and back, while larger vessels prioritize deck space and bar service. Capacity varies — smaller boats cap at thirty passengers, the DJ cruises accommodate two hundred — and evening slots fill fastest on Friday and Saturday. The St. Lawrence current runs at four knots during ebb tide, so captains time routes to ride the outbound flow and motor against the return. Navigation lights trace the shipping channel, and the Quebec Bridge's cantilever spans mark the upriver horizon. The experience is transactional: tickets specify departure time, vessel type, and whether food or drink is included. No two operators offer identical itineraries, so choosing well depends on whether you want commentary, music, or silence on the water.