Whether a day trip to Quebec City from Montreal is "worth it" depends on your tolerance for travel time, but most visitors find the experience highly rewarding. The journey takes about 3 hours each way via the VIA Rail train or car, meaning you will spend 6 hours in transit for about 6–8 hours of sightseeing. Despite the long day, Quebec City offers a completely different atmosphere than Montreal; it is the only fortified city north of Mexico, and its UNESCO-listed Old Quebec (Vieux-Québec) feels like a slice of 17th-century France. A day trip is sufficient to see the iconic Château Frontenac, walk the cobblestone streets of Petit Champlain, and even take a quick trip to the nearby Montmorency Falls. If you enjoy history, European-style architecture, and picturesque "Old World" vibes, the effort is well worth it. However, if you prefer a slower pace, you may find the schedule too "hectic" and might prefer an overnight stay to enjoy the city’s romantic evening ambiance and world-class dining scene without watching the clock for your return train.