A ferry crossing is often the calmest part of travelling abroad with a dog, once you know which rules apply to your route. The catch is that "pet friendly" means very different things on different ships. On a short Dover–Calais hop, your dog will most likely stay in the car. On an overnight North Sea crossing, you may be booking one of a handful of pet cabins months in advance. Get the details right at the booking stage and the day itself tends to look after itself.

Start with the ferry company, not the destination

Operators set their own pet policies, and they vary by route as much as by company: how many dogs you can bring, whether pets are allowed in passenger areas, whether they must stay in the vehicle, and whether the ship has pet cabins at all. Some crossings don't accept foot passengers travelling with a dog, so if you're sailing without a car, check before you build a plan around it.

Assistance dogs are normally exempt from pet restrictions and stay with their owner in passenger areas. Confirm that when you book, particularly on older ships where space is tight. Pet fees are usually charged per animal, each way, and added at the time of booking, so declare your dog rather than arriving with one at check-in.

Short crossings: when your dog stays in the car

On many short sea routes the rule is simple. Your dog remains in the vehicle for the duration, and passengers aren't allowed back onto the car deck while the ship is at sea. That makes the car your dog's cabin, so prepare it like one.

Keep a window open slightly if the operator permits it, and think about the direction of the sun — a car that's shaded at check-in can be baking by the time you sail. In hot weather, choose an early or late crossing where you can, and ask about kennels if a heatwave is forecast. Leave a non-spill bowl of water and something that smells of home.

Give your dog a proper walk and a toilet break before you drive onto the deck, and mention to a crew member at check-in that you have a dog on board. They can then keep an eye on the vehicle deck. If the forecast is genuinely dangerous, a different sailing is a better answer than a cracked window.

Pet-friendly cabins and on-board kennels

Longer routes — the North Sea, the longer Channel crossings and several Irish Sea sailings — are where pet cabins earn their keep. They're limited in number, they sell out first in summer and around school holidays, and they come with conditions. The dog stays in the cabin with you, isn't left alone there, and travels on a lead in corridors and on outdoor decks. Restaurants, bars and shops are almost always off limits, so plan meals around one person staying behind or book a cabin near the facilities.

If you're booking a kennel instead

Where cabins aren't available, kennels often are. They're basic: a small pen with a latch and not much else. Bring your own bedding, bowls and water, and ask whether you're allowed to visit during the crossing — some operators permit it, others don't. Kennels are shared between sailings, so keep flea and worm treatment up to date. If your dog has never been kennelled, a trial night at home in a crate will tell you a lot before you commit.

Paperwork: what to sort before you reach the port

For a domestic crossing — the Isle of Wight, the Scottish islands, a short estuary hop — there's usually nothing beyond the operator's own rules. Travelling to the EU or to Northern Ireland is a different matter. Your dog needs to be microchipped, vaccinated against rabies and accompanied by the correct documentation issued shortly before travel. UK pet passports are no longer accepted for entry into the EU. Requirements for the return journey to Great Britain differ again, and can include tapeworm treatment depending on where you've been.

These rules change, and timing matters: documentation has to be issued within a set window before you sail. Confirm the current requirements on gov.uk and with your vet before you book anything non-refundable, rather than arranging an appointment for the day before departure. Carry the originals and a copy, and keep vaccination records with you.

Pet travel rules, veterinary requirements and medication advice all sit outside the scope of a travel guide. Treat the above as a prompt to check, not as a substitute for official guidance or professional advice.

On board: keeping the crossing calm

Most dogs cope with ferry travel well when the routine around it is sensible. Walk yours properly before check-in, and give a light meal a few hours before boarding rather than a full one on the way to the port. If your dog suffers from motion sickness, ask your vet about suitable options. Don't reach for human travel sickness tablets or sedatives without veterinary advice — products and doses differ, and the wrong one causes more problems than a rough crossing would.

Pack a small bag you can grab without unpacking the car:

• Water and a collapsible bowl
• A day's food, plus any medication
• Poo bags, kitchen roll and an old towel
• A spare lead and a harness
• A familiar blanket or toy
• Vaccination record and travel documents

Check that the collar tag carries a mobile number that will work abroad, and that your microchip details are current. On boarding, keep the lead short, stay relaxed yourself and talk to your dog quietly. They take their cue from you, and a calm owner is worth more than any gadget.

Before you sail

Confirm the pet policy for your exact route and ship, book cabins or kennels as early as you can, and check your documentation timing against the current rules. Plan the toilet stops on the drive to the port, and think about the other end of the journey too: pet-friendly accommodation, and whether the places you want to visit will accept a dog on a lead.

If your dog is elderly, anxious or unwell, speak to your vet before booking. Some journeys suit some dogs better than others, and changing plans a month out is far easier than doing it on the quayside. Sort the details in advance, and the ferry becomes the easy part of the trip.

Photo: Anastasiya Badun / Pexels