A cruise ship feels like it is barely moving, and compared with almost any other way to travel it is. That is mostly by choice: the ship could go faster, but the fuel bill says otherwise.
The short answer
Most modern cruise ships sail at 18 to 22 knots, which is about 33 to 41 km/h (21 to 25 mph). Their top speed is usually a little higher, around 22 to 25 knots, but they rarely use it.
Typical speeds by ship type
- Large ocean cruise ships: service speed around 20 to 22 knots (37 to 41 km/h)
- Mid-size and older cruise ships: usually 18 to 21 knots (33 to 39 km/h)
- Expedition ships: often 12 to 16 knots (22 to 30 km/h), built for ice and small ports rather than speed
- River cruise boats: roughly 10 to 13 knots (19 to 24 km/h), and slower going upstream
- Queen Mary 2: an ocean liner rather than a cruise ship, with a service speed of about 26 knots and a top speed close to 30
Why ships rarely go flat out
The power a ship needs rises very steeply with speed: roughly with the cube of it. Slowing from 22 knots to 18 knots cuts the power needed by around 45%, and because the trip takes longer, the fuel used per nautical mile still drops by about a third.
Itineraries are planned around that. Most port-to-port legs are short enough to cover overnight at a relaxed 15 to 18 knots, which also makes the ride smoother. The extra speed is kept in reserve for bad weather, a late departure or a medical diversion.
How far a cruise ship travels in a day
At 20 knots a ship covers 480 nautical miles in 24 hours, which is about 890 km or 550 miles. On a typical sea day at a more economical 17 to 18 knots, expect something closer to 400 to 430 nautical miles (740 to 800 km).
What is a knot?
A knot is one nautical mile per hour. One nautical mile is 1,852 metres, so one knot is 1.852 km/h or about 1.15 mph. Ships and aircraft use it because a nautical mile matches one minute of latitude, which keeps chart navigation simple. Our guide to knots, mph and km/h goes deeper, and the speed converter switches between all of them.
The fastest passenger ships
The record for an ocean liner still belongs to the SS United States, which averaged more than 34 knots on its record Atlantic crossing in 1952. Modern cruise ships are not built to compete with that: they carry far more weight in cabins, pools and theatres, and they make their money on comfort rather than speed.
Checking your ship's speed with your phone
GPS works well on a ship as long as the phone can see the sky. On an open deck or a balcony you will usually get a solid fix within a minute; deep inside the ship, in an interior cabin, the signal is often too weak. Our ship speed test shows your speed in knots, km/h or mph straight from the browser, and the boat speed checker does the same on smaller craft.
Many ships also show their speed and position on a navigation channel on the cabin TV, which makes a handy cross-check against the GPS reading.
The takeaway
18 to 22 knots is the normal cruising range, with a few knots in reserve above that. Ships could go faster, but the fuel cost climbs so steeply that slow and steady is what keeps the itinerary affordable.