Planning an island trip around distance produces itineraries that cannot be flown or sailed. The binding constraint is the timetable, which exists to serve residents and freight rather than visitors.
Frequency, not distance, sets the journey
Two islands a short distance apart may have no direct sailing at all, because routes radiate from a mainland port rather than connecting neighbours.
Travelling between them therefore means returning to the hub and departing again, which can convert a short crossing into a full day.
The pattern is a hub-and-spoke network shaped by where the vessels are based and where they overnight, not by geography.
Timetables are built around resident needs
Sailings are scheduled so that islanders can reach mainland appointments and return the same day, and so that freight arrives when businesses can receive it.
That produces early departures and late returns, with an unhelpful gap through the middle of the day when a visitor would prefer to travel.
School terms, hospital clinics and market days all leave visible fingerprints on which days carry extra sailings.
Seasonality is severe
Many routes run several times daily in summer and drop to a few sailings a week outside it, with some seasonal routes stopping entirely.
Winter timetables are published later and are more subject to change, since vessels are rotated out for annual maintenance during the quiet months.
An itinerary designed from a summer timetable can be impossible in the shoulder season even though every island on it is still inhabited.
Weather cancels sailings without much warning
Exposed crossings are cancelled on wind and swell thresholds, and the decision is often made only a few hours ahead.
Cancellations cluster, so a disruption typically costs more than one sailing and the backlog takes days to clear on a low-frequency route.
Vehicle bookings and foot passengers are handled differently when services resume, and vehicle space is usually the harder of the two to recover.
Building an itinerary that survives
Leaving a spare day before any onward flight is the single most effective precaution, and it matters more the smaller the island.
Vehicle space on popular summer routes sells out well ahead, so a car booking is the element to secure first and the accommodation second.
Spending more nights on fewer islands almost always produces a better trip than chaining short stays, because each hop consumes a large part of a day.