Ferries run on tides, weather and the vehicle deck

Everything below about travelling by ferry comes from what actually happens rather than from what is supposed to.

The timetable is a physical constraint

Tidal ports can only be entered within a window either side of high water, which is why some routes sail at times no passenger would choose. Turnaround requires unloading vehicles, cleaning, refuelling and reloading in sequence, so a delay on one crossing shifts the whole day. Seasonal timetables change substantially, and winter frequencies on many routes are a fraction of summer ones.

Reading a ferry timetable as if it were a bus schedule is the first mistake people make.

Weather cancels ferries far more than flights

A ferry cancels on wave height, wind direction relative to the berth, and swell, all of which can be marginal in conditions that look unremarkable from shore. Small vessels on exposed crossings are the most affected, and some routes have a genuinely poor winter reliability record. Operators usually publish a decision a few hours ahead, which is little use if you have already travelled to the port.

At the airport, building a spare day into any itinerary that depends on a single crossing to catch a flight is standard practice for a reason.

Foot passengers and vehicles are different queues

Vehicle check-in typically closes far earlier than foot passenger check-in, because loading a deck is a sequenced operation. Foot passengers may board through a separate terminal, by a shuttle bus, or in some ports not at all, since some vehicle ferries do not accept them.

At the airport, booking a vehicle requires accurate length and height, and exceeding the declared dimensions can mean being refused or recharged at the port. Check which category you are in before assuming the published departure time is your deadline.

Cabins and overnight crossings

On overnight routes a cabin is the difference between arriving rested and arriving having sat in a lounge chair all night. Cabins are limited and sell out well before deck space, particularly in summer and around public holidays. Reclining seats are the intermediate option and are usually assigned rather than chosen.

As with sleeper trains, the honest comparison is against a hotel plus a day of travel rather than against the cheapest fare.

Motion and how to reduce it

A vessel moves least near its centre, low down and amidships, which is where the more expensive cabins usually are for exactly that reason. Fresh air and a view of the horizon reliably help motion sickness; reading below deck reliably does not. Remedies are available over the counter in most countries, and anyone considering medication should ask a pharmacist about interactions and drowsiness.

Crossings with a following sea feel very different from the same route in the other direction, which is why one leg can be fine and the return unpleasant.

Allowances vary by fare class more than by airline.

Booking and price behaviour

Vehicle fares vary enormously by season, day and sailing time, and midweek off-peak crossings are often a fraction of weekend prices. Some routes are effectively public services with fixed fares; others are commercially yield-managed like airlines. Island routes frequently offer resident and multi-trip discounts that visitors cannot use.

Where a route is the only link to an island, book well ahead, because capacity is genuinely finite and does not expand for demand.

The takeaway

Check the sailing forecast and the check-in deadline for your category, and never make a ferry the last link before a flight.

Pack for the trip you are actually taking, not the one in the photographs.