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How Long Can a Cruise Ship Stay Out At Sea For?

If you’ve ever considered taking a cruise you may be wondering how long a cruise ship could stay at sea for without needing to refuel. It isn’t uncommon for cruise ships to spend a week at sea but a longer period of time is possible. I’ve been on numerous cruises but haven’t ever been continually at sea for more than three days.

How Long Can a Cruise Ship Stay at Sea For?

Generally speaking, cruise ships can only stay at sea for around twelve days before they need to refuel. Despite this most cruise ships will refuel every few days as they stop at different ports. Just because a cruise ship could in theory stay at sea for 12 days, this doesn’t mean that they do. 

Cruise ships often sail for days across the Atlantic or Pacific oceans, when they do this they must make sure that the journey is carefully monitored so that the ship does not run out of fuel. 

Repositioning cruises which start and end in different places such as a transatlantic or transpacific cruises are some of the best value for money cruises on the market, to find out why, and how to find the cheapest cruises, check out this post: 7 Benefits of Repositioning Cruises (Tried & Tested)

In this post we look at what would happen when a ship runs out of fuel while at sea and how the type of ship affects how long it can be at sea for.

cruise ship

What Affects a Cruise Ships Fuel Usage?

Several different factors can change the length of time a cruise ship can last at sea before needing to refuel:

      • Ship size – The size of cruise ships varies dramatically with some holding as little as 100 passengers and others carrying upwards of 6000. Rather unsurprisingly, bigger cruise ships need to use more fuel! Larger cruise ships do however have the capacity to hold more fuel so this doesn’t mean that bigger ships can’t stay as sea for as long as smaller ships. 
      • Age of the ship – Generally speaking newer cruise ships are more fuel efficient than older ships. There are many cruise ships from the 70’s, 80’s and 90’s which are still in operation which use dramatically more fuel than newer ships. Even within the same cruise line there can be big differences, the Norwegian Spirit is one of the oldest ships for Norwegian Cruise Line and she is far less fuel efficient than the newer Norwegian cruise ships.
      • Average speed of the sailing – Cruise ships can burn through over one thousand gallons of fuel every hour when sailing. Generally speaking the faster a cruise ship sails the most fuel it has to use to do that. If a cruise ship is travelling fast to avoid a storm or to reach a destination in a short period of time it’ll use more fuel than if travelling slowly. To learn more about how, and why, a cruise ship would sail at an increased speed to avoid bad weather, check out this article: 5 Ways Cruise Ships Avoid Bad Weather.

Cruise lines spend on average 8% of your cruise fare on fuel. Fuel is one of the biggest costs that a cruise line has so they are always keen to reduce this. Check out the video below to learn what the other 92% of your cruise fare is spent on.

Cruise Ship Innovation

Many cruise lines are working hard to find new and innovative ways to preserve energy and fuel. This SHOULD allow the cruise lines to go longer between refuelling or simply allow the cruise ship to carry and use less fuel. 

Viking have created some of the most sustainable cruise ships to date:

The ship is powered by energy-efficient hybrid engines, hydro-dynamically optimised and streamlined hulls, and bows designed to achieve maximum fuel efficiency. It also incorporates on-board solar panels, and use equipment that minimises exhaust pollution while meeting environmental regulations. – source.

viking cruises umbrella

Me with the Viking Sea in Norway

Carbon Neutral Cruise Lines

All cruise lines are conscious of their carbon footprint and are seeking to reduce their impact as much as they can. MSC are the first major cruise line to off set all of their carbon emissions making their cruises carbon neutral. As time goes on there is expected to be more and more restrictions placed on cruise ships so it’s important that lines strive to be as economical as possible in order to future proof their cruise ships.

Does Cruise Ship Type Affect How Long It Can Last at Sea?

Different types of cruise ships will be able to last for different periods of time at sea:

The different types of cruise ships are: 

  • Ocean Cruise Ships – This is the most common type of cruise ship, as it offers a wide variety of activities and amenities, onboard. If you are considering a cruise on any of the major cruise lines it’s likely that you’ll be cruising on a mainstream cruise ship. These cruise ships often have diesel engines that use “heavy fuel oil.” When cruise ships reach a certain size they are often referred to as ‘mega ships’ which, rather unsurprisingly, require more fuel. Harmony of the Seas is a mega ship and she has has two engines which at full power burn about 66,000 gallons a day.
  • Ocean Liners – Ocean liners are often confused with cruise ships but there is a difference. Ocean liners are designed to transport guests from point A to point B where as cruise ships are designed as more of a leisure activity. Ocean lines are designed to travel longer distances and generally can go faster than cruise ships. That said, there is only one ocean liner still in operation, Cunard’s Queen Mary 2. To learn more about ocean liners, check out this post: Cruise Ships vs Ocean Liners: 5 Fundamental Differences
  • River Cruise Ships – River cruise ships are designed for short cruises and because of their size they don’t carry as much fuel. On the majority of river cruises you won’t have any ‘river days’ in the same way as you’d have a sea day on an ocean cruise. If a river cruise ship was in danger of running out of fuel at any point it would be able to sail towards the shore without too much trouble. 
Saga River Cruise Exercise

Me onboard a Saga river cruise ship, passing through a lock

It’s very important for a cruise ship to make sure that it has enough fuel to complete its journey, that said, no cruise ship wants to sail with extra fuel onboard. 

What Happens If a Cruise Ship Runs Out of Fuel?

Cruise ships are not designed to be able to refuel while they are out at sea and it is incredibly unlikely that a cruise ship would run out of fuel and be unable to find somewhere to dock to refuel. If this did happen the passengers and crew would have to be evacuated either using lifeboats or by air. 

Without fuel the cruise ship wouldn’t be able to work the toilets, raise the anchor, or do almost anything onboard. It would be very unpleasant and dangerous to be onboard.

To learn more about how cruise ships on toilets work, including what you can’t EVER put down a cruise ship toilet, check out the post below:

Cruise Ship Toilets: What Happens When You Flush? Step by Step Guide


Cruise ships are equipped with lifeboats to ensure safety for all passengers. Emergency plans of action are directly set into place in case of an emergency. Crew members and all administrators on board are well versed as to how they need to behave and what needs to be done during situations of crisis.

On every cruise it is a legal requirement that all guests attend a muster drill in order to familiarise themselves with the safety procedures onboard. To learn more about muster drills, including what happens if you don’t attend. Check out this post: What is a Muster Drill on a Cruise? Everything You Need to Know

Life Jacket Selfies What Is a Muster Drill?

In Conclusion

A cruise ship is capable of remaining at sea without refuelling for around twelve days. Most ships will never be at sea for this length of time though, with the majority completing journeys of 7-10 days or less.

average cruise duration 7 nights

If a cruise ship did completely run out of fuel at sea the guests would have to be evacuated as soon as possible as this could be very dangerous for all involved. 


Want to learn how to cruise well on a budget? Start here: How to Cruise For Less

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