When a cruise boat stops at a port, thousands of tourists descend upon its city en masse - which might not be so great for those not coming from the boat.
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While popular European destinations are already overrun during peak summer months, cruise ships add thousands of tourists entering a city in one day, congesting all the popular sights and creating long queues.
One handy tool to help you suss out how to spot the busiest periods is Avoid Crowds - a website that uses tourism data like cruise ship schedules and holidays that will tell you what the crowd would be like in any big city.
We had a look at some of the busiest port cities and when's the best time to avoid their cruise season.
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Cruise season: April to November, while October will be the busiest month followed by May.
Cruise season: There's an expected 8% increase in cruise passengers predicted for 2020, starting in May and ending in October. The end of the season is the busiest.
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Cruise season: April to October, while the busiest month is September followed by May and August.
Cruise season: May until October, peaking in August.
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Cruise season: March to October, with June and September as the bearing the brunt of the crowds.
Cruise season: May to October, with the last month being the busiest.
Cruise season: High season is between May and September, although the year-round destination gets cruise ships from January to November.
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Cruise season: April to October is peak season, with May and October as the busiest times.
Cruise season: September to October, with the last month of the short season seeing the most cruise passengers.
Cruise season: May to September is this city's cruise season, peaking in July and August.
Cruising season: Starts in April all the way to November.
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