Ferries vs flights: the honest math
The €29 flight is not €29 and the €140 ferry is not €140. Everyone knows this and almost nobody acts on it, because the fares are what the search results show you and everything else has to be worked out by hand.
It takes about five minutes and it changes the answer more often than you would expect. Here is the method.
Cost the flight properly
Start with the fare — a flight metasearch shows the spread across carriers in one look — then add every line that is not optional for the way you actually travel.
Checked baggage, if you need it, priced per bag per direction — this is where the budget carriers make their margin and it is frequently more than the fare. Seat selection, which becomes near-compulsory the moment you are travelling as a group and want to sit together, or with a child. Any card or payment surcharge.
Then the two ends. Airport transfer at the origin, airport transfer at the destination, both priced for the actual time of day, because the 05:00 departure means a taxi rather than a bus.
Budget carriers use secondary airports, and this is often the deciding factor rather than a footnote. An airport an hour outside the city can cost €20 and 90 minutes each way, in each country, which is €80 and three hours added to a €29 fare.
Finally, cabin baggage rules are still airline by airline as of mid-2026. The EU standard shape is a personal item of up to 40 × 30 × 15 cm that fits under the seat, and the guaranteed free cabin bag arrives with the passenger-rights reform expected to apply from 2027 — not yet. Until then, check the specific airline.
Cost the ferry properly
The fare, again first, then the additions — which are fewer but larger.
A cabin, if the crossing is overnight and you want to arrive functional. On a long overnight route this is not optional in any meaningful sense; deck class before a day of driving is a false economy.
The vehicle, if you have one, priced by length and height. Roof boxes and bike racks push some cars into the next band, so measure rather than guess.
Then the ends, which are usually the ferry’s advantage: ports tend to sit in or near the town, and the transfer is short. Not always — some ferry terminals are as remote as any low-cost airport — so check rather than assume.
And check-in, which is typically 60 to 90 minutes before departure rather than the two hours plus security queue that flying involves.
The car is not a line item, it is a different problem
This is the structural point, and it is why the comparison is not really one comparison at all.
A car and everything in it travels free of weight rules and liquid rules. No 23 kg limit, no 100 ml bottles, no measuring the cabin bag against a metal frame. A pushchair, a cool box, four pairs of ski boots, a case of wine and the dog all just go in.
For a solo traveller with a backpack this is worth nothing. For a family of five with a fortnight’s luggage it is worth several hundred euros in avoided baggage fees plus several hundred more in not hiring a car at the other end, plus the thing that does not appear in any spreadsheet, which is not having to think about any of it.
So the honest answer to “ferry or flight” depends less on the route than on what you are carrying and how many of you there are.
An illustrative worked example
The numbers below are invented to show the shape of the arithmetic. They are not a real route and should not be used as a price guide — put your own figures in.
| Line | Flight, 2 adults | Ferry, 2 adults + car |
|---|---|---|
| Fare | €58 | €190 |
| Bags / vehicle | €90 (2 bags, both ways) | €95 (car) |
| Seat selection | €24 | — |
| Cabin | — | €70 |
| Transfers, both ends | €120 | €15 |
| Car hire at destination | €210 | — |
| Total | €502 | €370 |
| Door-to-door time | 7h 30m | 11h |
The pattern that example is showing is the one you should expect: the flight wins on fare and loses on everything attached to it, and the car hire line is often what decides it.
Run the same table with one person and a backpack and it inverts completely — no checked bag, no car at either end, and the flight wins by a distance.
Total door-to-door time, not flight time
Count from your front door to your accommodation.
For the flight: transfer to airport, two hours before departure, flight time, disembark and baggage reclaim, transfer at the far end. A 90-minute flight is reliably a six- to seven-hour day.
For the ferry: transfer to port, an hour or so of check-in, crossing time, transfer at the far end. An overnight crossing that you sleep through costs you almost no waking time at all, which is a genuine advantage the clock does not show.
Where the answer is reliable
Short sea crossings with a car. Ferry, almost always. The flight equivalent means hiring a car at the other end and the maths is not close.
Long north–south journeys with no car and no luggage. Flight. A backpack and a cheap fare will beat two days of surface travel on both cost and time, and pretending otherwise is romanticism.
An island with an airport but a two-hour ferry. Usually the ferry, once you count the transfers. Island airports are frequently far from the main town, the flights are few, and the fares are protected.
Six or more people with luggage. Do the maths, but the ferry wins more often than people expect — group fares exist on ferries, baggage costs scale linearly on flights, and one large vehicle carries what six air passengers cannot.
Carbon, honestly
The comfortable answer is that the ferry is greener. The true answer is that it depends on the vessel, its speed, its occupancy, and how you allocate a ro-ro ship’s fuel between passengers and the freight it also carries.
Standard emissions factors, including the UK government conversion factors widely used across Europe, put a foot passenger on a conventional ferry at roughly 19 g CO2e per passenger-kilometre against roughly 190 g for a short-haul flight seat. That is a tenfold difference and it is real for that case.
But a high-speed catamaran running half empty can come out above a full aircraft on the same corridor, and some analyses put ferries above flying per passenger-kilometre for exactly that reason. A big, slow, full, freight-carrying ferry is excellent. A fast, light, half-empty passenger-only craft is not.
If carbon is genuinely part of your decision, the conventional ferry is the choice, not the ferry in general.
The exception: cancellation risk is not symmetric
This is the thing that should change a tight itinerary, and almost nobody prices it.
If your flight is cancelled or badly delayed, EU air passenger rights give you a well-defined regime: re-routing at the airline’s cost, care while you wait, and compensation of €250, €400 or €600 by distance band at a three-hour arrival delay, as the rules stand in mid-2026. Airlines fly the route several times a day, so re-routing usually means hours.
Ferry passengers have rights too, under the EU maritime passenger regulation, but the remedies are thinner. Compensation is a percentage of the ticket price rather than a fixed sum — 25% at delay thresholds that scale with journey length, rising to 50% if the delay doubles — and weather cancellations are excluded from compensation entirely.
More to the point, the next sailing may be tomorrow. On a route with one boat a day, or a route shut down by wind, there is no equivalent of the 18:40 departure.
So if your onward connection is tight, or you are sailing on the day of an international flight, the ferry carries a risk the flight does not. Build a buffer night in, or take the plane.
How we make money on this
Sometimes the honest answer here is the €29 flight and sometimes it is staying put and booking nothing at all, which pays us nothing — we’d publish it either way.