River Cruises are Busy.

Unlike ocean cruises that offer “sea days” with plenty of time to relax, voyages along European waterways include a stop each day with a busy — albeit completely optional — sightseeing program. So if you want to make the most of your trip, there isn’t always as much time to chill out onboard as you might think.

More is Included.

With the exception of a few lines that offer an “a la carte” shore excursion schedule, daily tours are usually included in the cruise fare. They range from introductory walking and motorcoach tours of towns and cities along the route, to immersive experiences such tours of ancient castles, vineyard visits and food tastings. Some lines also offer extra fee options that are a bit more unusual, including bike tours, exclusive evening concerts, cooking classes, art lessons and even the chance to conduct an orchestra in Vienna.

They differ from ocean cruises.

The majority of river cruises are a week long — typically taking in three countries — with some lines offering longer trips from 10 days to two weeks or more. They almost always start in fantastic cities such as Paris, Amsterdam and Budapest, and most itineraries include an overnight onboard. Companies also offer pre- or post-cruise stays so passengers can spend more time in these cities.

It should be noted that virtually all ships on the Rhine and Danube are exactly the same size in order to fit into locks and pass below bridges. Price differences in fares reflect the number of passengers (the more expensive lines carry less people, others up to 190), onboard facilities such as massage rooms and gyms, plus inclusions (some lines include all drinks and gratuities).

There is seasonality.

One final caveat about cruising Europe’s rivers: Aside from special Christmas market and New Year cruises, the season typically runs from April to October. Be aware that heavy rain and spring flooding can make the rivers swell and the locks become impassable. (Many are under bridges, so if the water is too high, boats can’t fit underneath.) Similarly, during long dry periods, low water can be a problem. If vessels can’t move, you’ll be taken to the sights by motorcoach or, if the logistics allow, moved to another ship further along the river.