You cannot walk out of this port
Zeebrugge is a working freight harbour and pedestrians are not allowed to walk through it, so even the passengers planning to do Bruges on their own start on a bus. A free port shuttle runs from the ship to the port exit. From there the do-it-yourself route is the coast tram: walk about 500 m to the Zeebrugge Kerk stop by the church, ride the tram toward De Panne to Blankenberge station, and pick up a train to Bruges.
The train leg is only about 15 minutes, hourly with extra trains at peak times. The slow part is stringing the shuttle, tram and train together, which is why the cruise-line and private shuttles that go straight into Bruges make sense even for passengers who otherwise skip ship excursions. Bus 40 also runs to Bruges, but the trip takes about an hour.
Bruges on a day-tripper's clock
Bruges has been trying to manage crowds since 2018, when it counted 8.3 million visitors - a jump of 900,000 in a year - and at peak times tourists outnumbered residents three to one. In 2019 the city stopped advertising for tourists and began encouraging cruise calls on weekdays rather than weekends.
The medieval centre is small and the streets are narrow, so a midweek call with several ships in still feels busy around the Markt. Getting into town early, before the coach groups, buys the quietest hour of the day.
Sources: whatsinport.com, cruisemapper.com