Quick answer: The best dog carrier for a small dog is a structured, well-ventilated bag with a waterproof outer, a washable padded base, and a secure clip to stop them jumping out. Soft slings suit very small dogs for short trips; structured shoulder carriers are better for longer days out because the dog can actually sit, turn and settle. Always check your dog's weight against the carrier's limit, measure for length and height, and prioritise ventilation and a stable base over how the bag looks. A good carrier isn't about carrying the dog — it's about giving them a den they'd choose to climb into.
Why the right carrier matters more than people think
Plenty of dogs love coming along — the picnic, the train, the long warm day in town. The difference between a happy passenger and a stressed one is almost always the bag. A flimsy carrier that sags, swings and traps heat makes the dog tense and fidgety; a structured, breathable one gives them a stable little den they settle into and fall asleep in. If your dog is small enough to travel this way, the carrier is the single thing that decides whether the day out is a joy or a battle.
There's a practical side too. The right carrier keeps your dog secure in crowds and on public transport, shields them from rain and sun, and — crucially in summer — lets them rest in shade rather than be carried, overheating, in your arms. This guide walks through exactly what to look for, the types available, how to size one, and which features genuinely matter.
What to look for in a dog carrier
Whatever your budget, these are the features that separate a real carrier from a bag with a zip:
- Ventilation. Mesh panels or breathable sides are non-negotiable. A dog can overheat quickly in an enclosed bag, so airflow is the most important safety feature there is.
- A structured, stable base. The dog should be able to stand, turn around and lie down without the floor folding under them. A wobbly base makes dogs anxious; a firm one lets them settle.
- A secure clip or tether. An internal carabiner or leash clip that attaches to the collar or harness stops a startled dog leaping out. This is essential safety kit, not an extra.
- Waterproofing. A water-resistant or waterproof outer means a sudden British shower doesn't end the day — and wipes clean after muddy paws.
- A washable interior. A removable, machine-washable pad is the difference between a carrier you use for years and one you quietly retire after one accident.
- A comfortable carry. A padded, adjustable shoulder strap matters a lot once you're carrying real weight across a long day. Test how it sits on you, not just on the shelf.
- The right size and weight limit. More on sizing below — but always check the maximum dog weight before anything else.
Types of dog carrier, and who each suits
Structured shoulder carriers
These are the all-rounders: a firm base, breathable sides, a zip top and a shoulder strap. They're the best choice for small dogs on longer outings because the dog can genuinely settle inside, and the structure protects them in a crowd. Many double as a cosy bed when you arrive. If you want one carrier that does the train, the café and the picnic, this is the category to shop in.
Soft slings
A sling holds a very small dog against your body, hands-free. They're light and lovely for quick errands and tiny dogs, but they offer less structure and ventilation, and an anxious dog can wriggle free more easily. Great as a second, short-trip option; less ideal as your only carrier for full days.
Backpack carriers
Worn on the back, these spread weight well and free both hands — handy for cycling-adjacent trips or long walks where you'll carry the dog part of the way. Look closely at ventilation, as some enclosed "bubble" designs trap heat. Best for confident dogs who don't mind being behind you.
Wheeled and trolley carriers
For heavier small dogs, older dogs, or anyone who can't carry weight comfortably, a wheeled carrier takes the strain. They're bulkier and less suited to stairs and busy public transport, but excellent for airports and long flat distances.
How to size a dog carrier correctly
Getting the size right is where most people go wrong. Too small and the dog can't turn around; too big and they slide about and feel unsteady. Here's the simple method:
- Measure length. From the base of the neck (where the collar sits) to the base of the tail. The carrier's internal length should be a little longer than this.
- Measure height. From the floor to the top of the shoulders when standing. The dog should be able to stand without crouching.
- Check the weight limit. Weigh your dog and compare it to the carrier's stated maximum. Don't push it — the limit is about the base and seams holding safely.
- Allow room to settle, not to roam. A carrier should feel like a snug den, not a kennel. Snug-but-not-cramped is the goal: enough to lie down and turn, not so much that they're thrown around as you walk.
If your dog is between sizes, size up slightly for comfort — but never so much that the carrier becomes unwieldy on your shoulder.
Our pick: the Soho Poms Rainy Bear Pet Carrier
If you want a structured carrier that ticks the boxes above, the Soho Poms Black Rainy Bear Pet Carrier (£69.99) is the one we reach for. It's made from hard-wearing waterproof canvas, so a sudden shower or a muddy paw doesn't faze it, and the interior is a cosy, highly water-repellent fleece-style lining with a removable cushion you can take out and wash. Practical details do the heavy lifting: a zip top keeps the dog safe and secure, a zip-up side pocket holds the essentials, and it comes with a carabiner to clip to a collar or harness so a startled dog can't leap out.
The clever bit is the flexibility — the sides roll down to create a sturdier, more supportive structure, effectively turning it into a cosy floor bed when you arrive somewhere. That means the dog travels in a den they recognise and then rests in the same den at the picnic or the café. It comes in three sizes (Small, Medium, Large), suits cats as well as dogs, and the adjustable strap makes carrying genuinely comfortable across a long day. At £69.99 it sits comfortably over our £30 free UK delivery threshold, so it arrives free.
One honest note: this is a carrier built for small dogs and cats — measure your dog using the method above and pick the size against the dog, not the breed name. If you're between sizes, the Medium and Large give a little more room to settle.
Using a carrier safely in hot weather
Summer is exactly when a good carrier earns its keep — and exactly when a bad one is dangerous. An enclosed, poorly ventilated bag can become an oven, so the same heat rules from our guide to keeping your dog cool in hot weather apply: keep the carrier in shade, never leave a dog inside one in a parked car or hot room, and offer water regularly. A structured, mesh-ventilated carrier with a washable base is the safe choice precisely because air can move through it. If the dog is panting heavily or looks distressed, take them out, into shade, and cool them down before going on.
Helping a new dog love their carrier
A carrier works best when the dog chooses to be in it. Build the association gently: leave it open at home with the cushion in and a favourite toy or a few treats inside, so they explore it on their own terms. Feed a meal near it, then in it. Do short carries around the house and garden before the first real outing, and keep early trips brief and positive. Within a week or two, most dogs treat the carrier as a portable safe space — which is the whole point.
Get the bag right and everything downstream gets easier: the train is calm, the café is relaxed, and the dog who insists on coming everywhere actually travels like they'd choose to. That's the difference between carrying a dog and giving them a den.
Frequently asked questions
What size dog can go in a carrier?
Carriers are designed for small dogs and cats, typically up to around 7–8kg depending on the model — always check the specific carrier's stated weight limit. Measure your dog's length (neck to tail base) and standing height, then choose a carrier a little longer and tall enough for them to stand. Larger dogs need a different approach to travel, such as a car harness or crate.
Are dog carriers allowed on public transport in the UK?
Policies vary by operator, but most UK trains and buses allow small dogs in carriers, and many allow dogs on leads too. A secure, enclosed carrier is often the easiest option in busy or crowded settings. Always check your specific operator's pet policy before travelling, as some peak-time or space restrictions apply.
How do I get my dog used to a carrier?
Introduce it slowly at home: leave it open with the cushion and a toy inside, feed treats and then meals near and in it, and do short practice carries before any real trip. Keep early outings brief and positive. Most dogs come to see a well-fitted carrier as a portable den within a week or two.
Is a sling or a structured carrier better?
Slings are light and hands-free, ideal for very small dogs on short errands, but offer less ventilation and structure. Structured shoulder carriers are better for longer days out because the dog can sit, turn and settle securely, and they protect the dog in crowds. For one do-it-all carrier, choose a structured design.
How do I clean a dog carrier?
Choose a carrier with a removable, machine-washable pad and a wipe-clean or waterproof outer. Wash the pad regularly, wipe the shell after muddy or wet trips, and air it fully before storing to prevent odours. A waterproof canvas outer, like the Rainy Bear carrier's, makes this much easier.