Coastal destinations behave differently from cities in how their accommodation sells, and the strategies that work for a city break work badly here.
Why coastal supply is inelastic
The structural reason everything else follows from.
A city can absorb more visitors by filling rooms that already exist, spread across a large area. A small coastal town has a fixed and often small number of beds, in a very limited area, with no ability to add more.
Planning restrictions on coasts are frequently strict, which is generally a good thing and which caps supply permanently.
So demand rises through the season against a fixed supply, and the result is genuine sell-outs rather than merely high prices.
This is why the city strategy of waiting for a late deal fails on a coast. There is no unsold inventory to discount.
The booking curve
What I have observed across a lot of trips and a lot of monitoring.
Peak weeks in popular coastal towns are substantially booked six months out and largely gone by three.
What remains close to the date is the least desirable stock at the highest prices, which is the opposite of a late deal.
Shoulder season behaves more normally, with availability a few weeks out and reasonable prices.
Off season is entirely different, with more availability than demand and genuine flexibility.
Which means how far ahead to book depends entirely on when you are going, and the general advice about booking windows is useless without that.
The repeat guest problem
A factor specific to coastal accommodation that surprises people.
Many small coastal properties have a substantial proportion of guests who return annually, frequently to the same week and the same room, booked before they leave.
In some places that accounts for most of the peak season inventory before it is ever advertised.
Which means the availability you see online for a popular small property in August may be a small fraction of the rooms, and the good ones went eleven months ago to somebody who has been coming for a decade.
The practical response is that if you find somewhere you like, booking next year before you leave is not excessive planning, it is how the market works.
Minimum stays
A coastal-specific complication.
Many properties impose minimum stays in peak season, frequently a week, and frequently with fixed changeover days.
Which means a five day trip may be impossible, or may cost the same as seven, and a trip that does not start on the changeover day may not be bookable at all.
This applies particularly to self-catering and to islands, where changeover is coordinated with ferry schedules.
Checking this before planning dates saves a lot of frustration, and being flexible about which day you start can open up options that appear unavailable.
What to do if it is all booked
Several things work and are frequently not tried.
Look slightly inland. A property two or three kilometres from the coast is a different market with different availability and substantially lower prices, and on most coasts that is a ten minute drive or a pleasant walk.
Look at the next town along, particularly the less famous one. Popularity is concentrated and unevenly distributed.
Contact properties directly and ask. Cancellations happen constantly and are not always relisted immediately, and a small place will remember an enquiry.
And consider the shoulder weeks, which for coastal trips are frequently better anyway for reasons to do with sea temperature and crowds.
Cancellation terms deserve attention here
More than in cities, because the commitment is longer and further ahead.
Booking six months out means six months of things that could change, and coastal properties frequently have stricter terms than urban hotels because a cancelled week in August cannot be resold.
Free cancellation until a stated date is worth paying a little more for on a long-lead booking, and the difference is usually modest.
Reading the specific date by which it becomes non-refundable, and putting it in a calendar, is a two minute job that has saved me twice.
What the photographs will not show
Booking six months ahead means committing on images alone, so it is worth extracting more from them than usual.
Check the date of recent reviews for renovation work, which coastal properties do in the off season and which sometimes overruns into the season.
Check whether construction is visible in any recent guest photograph, since coastal development is constant and a building site next door is the most common serious complaint.
And look at the property on satellite view for what is immediately around it, which the listing photographs are framed specifically to exclude.
Paying in advance
A related consideration when committing far ahead.
Long-lead bookings frequently require a deposit, sometimes a substantial one, and occasionally payment in full months before arrival.
That is money at risk against a business that has to survive a winter, and small coastal operators do occasionally fail.
Paying by a method that offers some protection, rather than by bank transfer, costs nothing extra and is worth doing on anything paid a long way ahead.
It is also worth keeping the confirmation and the terms somewhere you will find them in six months, because you will not remember what was agreed.