Your cruising can contribute to something positive

What is a cruise carbon footprint?

A cruise carbon footprint is an estimate of the greenhouse gas emissions produced during a voyage, typically expressed in tonnes of CO₂ equivalent (CO₂e) per passenger.

Cruise ships burn large quantities of marine fuel — historically heavy fuel oil, increasingly blended with lower-sulphur alternatives — to move the vessel, power the hotel facilities, and operate in port. All of that combustion produces CO₂, along with smaller quantities of methane, nitrous oxide, and other gases, which are rolled into the CO₂e figure.

The footprint covers the journey itself: the nautical miles sailed, the days at sea, and the port operations. It does not typically include the passenger's flights to and from the embarkation port, which can add substantially to the overall travel footprint.

How much CO₂ does a cruise produce?

Research consistently finds that cruising is among the more carbon-intensive forms of holiday travel on a per-passenger-kilometre basis. Published figures from cruise industry research and academic studies suggest roughly 0.4 kg CO₂e per passenger per nautical mile as a working average across fleet types, though this varies considerably by ship age and fuel.

For a typical 7-night Caribbean cruise covering around 2,500 nautical miles and calling at 5 ports, SeaDays estimates approximately 0.65–0.80 tonnes CO₂e per passenger. A longer voyage — say, a 14-night transatlantic crossing covering 4,000+ nautical miles — might reach 1.3–1.6 tonnes per passenger.

Cruise CO₂ compared with other activities

Putting a voyage footprint into context makes it easier to understand what the number actually means.

Cruise vs. driving a car

The average petrol car emits roughly 4.6 tonnes of CO₂ per year, or about 0.38 tonnes per month. A 7-night cruise footprint of ~0.70 tonnes is therefore equivalent to approximately 1.8 months of average car use. A short 5-night cruise (~0.40 t) is closer to one month of driving.

Cruise vs. flying

A typical short-haul flight produces around 0.2 tonnes of CO₂e per passenger, while a long-haul intercontinental flight might produce 1.0–1.5 tonnes. Most 7-night cruises fall somewhere in between — meaning the voyage itself produces roughly the same footprint as three to four short-haul flights.

Cruise vs. everyday activities

A cruise footprint of 0.70 tonnes is equivalent to:

• Charging your smartphone approximately 14,000 times
• Leaving an LED lightbulb on for roughly 1.4 million hours (about 160 years continuous)
• The annual CO₂ absorption of approximately 34 mature trees

These comparisons illustrate scale — they are not suggestions that planting trees or changing lightbulbs offsets a cruise.

What cruisers can do to reduce their footprint

Individual choices around a cruise can shift the total footprint in meaningful ways.

• Choose a newer ship: Modern vessels are significantly more fuel-efficient than older fleets. Choosing a ship built in the last decade makes a real difference.
• Prefer LNG-powered ships: Liquefied natural gas produces roughly 20–25% less CO₂ per unit of energy than heavy fuel oil.
• Shorter itineraries: A 5-night cruise has a meaningfully smaller footprint than a 14-night voyage — even if the per-day rate is similar.
• Walk or use public transport at ports: The biggest post-voyage variable is what you do in port. Walking tours and local buses have a far smaller footprint than private taxis and excursion coaches.
• Combine cruise and fly smart: Taking the train to the embarkation port, or choosing a port close to home, removes a substantial source of travel emissions from the equation.
• Choose itineraries with fewer sea days: Sea days accumulate duration-based emissions; a port-heavy itinerary at a similar distance can produce a slightly lower overall estimate.
• Consider a carbon contribution: Inside the SeaDays app, you can use SeaDays Points to make a contribution against your estimated voyage footprint. This is recorded in the community total and is intended to prompt reflection, not as a certified carbon offset.