Carrying Case for Dogs: How to Choose the Right Size, Type, and Travel Rules

A carrying case for dogs is a portable, ventilated, leak-proof enclosure that lets a dog stand, sit, turn around, and lie down naturally while being carried by hand, on the shoulder, in a car, or under an airline seat. To choose one, measure your dog, apply the International Air Transport Association (IATA) sizing formula, pick the case type that matches how you travel, and confirm your airline's current limits. As of September 2026, no carrier is officially "IATA-approved."

This guide is written by the Animal Passport editorial team, which covers animal identity, movement, and welfare records. It draws on the IATA Live Animals Regulations, the U.S. Animal Welfare Act transport standards, airline policy pages, and independent crash-test programs. Where these sources disagree, we say so.

What is a carrying case for dogs?

A carrying case for dogs, also called a dog carrier, pet carrier, or travel kennel, is any enclosure designed to move a dog safely from one place to another. The category covers soft-sided bags, rigid plastic crates, backpacks, slings, wheeled carriers, and car-rated carriers that anchor to a seat belt.

Regulators describe the same object in more formal terms. United States federal rule 9 CFR 3.15, part of the Animal Welfare Act regulations enforced by the United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS), calls it a "primary enclosure such as a compartment, transport cage, carton, or crate." IATA calls it a container and sets its standard in Container Requirement 1 (CR1) of the Live Animals Regulations (LAR).

The one rule every source agrees on: stand, turn, lie down

Every authority we reviewed uses nearly the same space test. IATA's Traveler's Pet Corner (LAR 2026) says the animal needs "enough space to turn about normally while standing, to stand and sit erect, and to lie in a natural position." Rule 9 CFR 3.15(e) uses almost identical wording for dogs and cats in commerce. Delta Air Lines adds that the pet must be able to move around "without touching or sticking out from the sides."

That shared test matters more than any product label. A case that fits under a seat but cramps your dog can still be refused at check-in.

How to size a carrying case for dogs (IATA formula)

IATA publishes a formula for the minimum internal dimensions of a container for one animal. Measure your dog standing in a relaxed, natural position, then calculate:

1. Measure A: length from the tip of the nose to the base (root) of the tail.
2. Measure B: height from the ground to the elbow joint.
3. Measure C: width across the shoulders or the widest point, whichever is greater.
4. Measure D: height from the floor to the top of the head or the ear tip, whichever is higher.
5. Calculate length: A + half of B.
6. Calculate width: C x 2 (C x 3 for two animals, C x 4 for three).
7. Calculate height: D + the depth of the bedding.
8. Adjust for snub-nosed breeds: IATA says snub-nosed dogs need a container 10% larger.

Worked example: a small dog measuring 14 inches nose to tail base (A), 5 inches to the elbow (B), 5 inches across the shoulders (C), and 10 inches tall at the ear tip (D) needs an internal length of about 16.5 inches, a width of 10 inches, and a height of 10 inches plus bedding. That dog is right at the edge of a typical 18 x 11 x 11 inch in-cabin limit once you account for the case's walls and frame.

Two practical checks follow from the formula. First, compare the result with the case's internal measurements, not the outside dimensions on the box. Second, compare the case's external measurements with your airline's limit, because under-seat limits apply to the outside of the case.

Types of dog carrying cases compared

The right case depends on where the dog is going. The table below summarizes the main types and where each fits best.

Soft-sided vs. hard-sided

For in-cabin flights, soft-sided cases are the common choice. Delta Air Lines recommends "a soft-sided kennel with maximum dimensions of 18 x 11 x 11 inches since this fits most aircraft types." But IATA's in-cabin guidance warns that soft-sided containers "may compress when inserted under the seat," and that compressing the ventilation openings can cause "reduced ventilation and heat buildup." If you choose a soft case, pick one with a stiff frame that holds its shape.

For dogs flying in the hold, a rigid crate is the usual choice because it resists crushing and escape. IATA notes that some airlines restrict certain breeds and may apply stricter policies than CR1, so ask your airline which crate construction it accepts before buying.

Ventilation, floor, and labeling: where the rules differ

Sources agree that a case needs airflow, a leak-proof floor, and absorbent bedding. They disagree on the exact numbers, so the strictest rule that applies to your trip is the one to meet.

• IATA (in-cabin guidance): at least 16% of the area of the four vertical sides should be ventilation openings, and the container should be escape-proof, leak-proof, and carry a "Live Animals" label.
• 9 CFR 3.15(c), USDA APHIS: ventilation totaling at least 14% of the combined wall area, arranged on two, three, or four walls, with at least one-third of the ventilation on the upper half and rims that leave 0.75 inch (1.9 cm) of air space.
• Delta Air Lines (2026 policy page): a soft-sided kennel must be leak-proof with ventilation on 3 sides for domestic travel and 4 sides for international travel.

Rule 9 CFR 3.15 also requires a solid, leak-proof bottom, no sharp interior edges, handles that let the enclosure be lifted without tilting, and the words "Live Animals" in letters at least 1 inch high. These federal standards apply to people and businesses subject to the Animal Welfare regulations, such as dealers, carriers, and intermediate handlers, rather than to every private owner on a walk. They are still a useful quality checklist when you buy a case.

Carrying cases for dogs on airplanes

If your dog will fly in the cabin, the case becomes part of the airline's acceptance check. IATA's guidance says any container used in the cabin must meet CR1 "or it will be rejected by the airline for travel," and that only very small dogs will fit under aircraft seats.

Airline policies differ, so treat the following Delta Air Lines figures, taken from its official pet travel page in September 2026, as an example rather than a universal rule:

• The kennel must fit fully under the seat in front of you, and maximum dimensions depend on the aircraft.
• One pet per kennel, with exceptions for a female with an unweaned litter and for two same-breed pets aged 8 weeks to 6 months.
• Dogs must be at least 8 weeks old for domestic travel.
• The in-cabin fee is $150 each way within the U.S. and Canada for tickets issued on or after April 8, 2025, and $200 for international travel.
• You must remove your pet from the kennel at the security checkpoint, then keep it inside the kennel in the airport and on board.

For a side-by-side comparison of airline size limits, see our guide to airline dog carrier rules and sizes.

How many dogs can share one case?

Usually one. Rule 9 CFR 3.15(f) allows no more than one dog aged 6 months or older per enclosure when shipped by air carrier. IATA allows at most two compatible adult animals of up to 14 kg each in one container and says animals over 14 kg must be crated individually. Delta's cabin policy is one pet per kennel apart from the exceptions above.

Carrying cases for dogs in the car

A case that is fine for a flight is not automatically safe in a crash. The Center for Pet Safety (CPS), a U.S. nonprofit, runs a voluntary CPS Certified program in which manufacturers commit to "meet independently developed safety standards," monitor quality control, and make "a commitment to truth in marketing." CPS states it does not accept funding from pet product manufacturers.

As of September 2026, the CPS Certified list includes both enclosed carriers, such as the Away Pet Carrier and PawsInCar Expandable Pet Carrier, and hard kennels, such as sizes of the Gunner G1 Kennel. Certification applies to a specific model tested with a specific dog weight, so check the certificate for your model and your dog's weight before relying on it.

Step-by-step: choosing a carrying case for your dog

1. Decide the main use: cabin flight, hold, car, or walking. Each has different limits.
2. Measure your dog using the IATA A, B, C, D method and calculate minimum internal dimensions.
3. Check the external limit on your airline's own pet page for your aircraft, not on a retailer listing.
4. Confirm ventilation meets the strictest rule for your trip: 16% of four sides (IATA) or openings on 4 sides for international Delta flights.
5. Inspect the build: leak-proof floor, secure zippers or latches, no sharp edges, and a frame that does not collapse onto the dog.
6. For cars, verify certification on the Center for Pet Safety website rather than trusting packaging claims.
7. Train early. IATA advises letting the dog get used to the crate "a few weeks or months" before departure.
8. Avoid sedation unless a veterinarian directs it. IATA and its member airlines discourage sedatives for pets in transit.

Identification: what goes on and in the case

A carrying case protects the dog, but it does not prove who the dog is or who owns it. IATA recommends a microchip plus two collar IDs: a permanent tag with your home details and a temporary travel tag with a contact at your destination. Rule 9 CFR 3.15(h) requires shipping documents and care instructions to be attached securely to the outside of the enclosure when a dog is shipped in commerce. Label the case with your name, phone number, and destination as well.

For international trips, documents come from official channels, not from the case or any app. The U.S. Centers for Disease Control and Prevention (CDC) is the primary authority for dogs entering the United States, according to USDA APHIS's Travel With a Pet page (last modified March 20, 2026). USDA APHIS advises contacting a USDA-accredited veterinarian as soon as you decide to travel abroad.

Where Animal Passport fits, and where it does not

Animal Passport is a digital animal and livestock passport built on muzzle biometrics: an animal's nose print is unique, like a fingerprint. Using a phone, the record links owner, breed, estimated age, body condition, and vaccination history. Age is estimated from a dental photograph with a confidence score, and body condition is scored 1 to 5 from a side-profile photo.

This matters when physical ID fails. During livestock flood rescue in Pakistan in August 2025, Animal Passport records helped farmers reclaim animals after paper tags washed away. A tag clipped to a carrying case can be lost the same way.

To be clear, Animal Passport is not an EU pet passport, not a CDC or USDA APHIS travel document, and not a substitute for an airline's carrier check or a veterinarian's health certificate. It does not diagnose illness. Use it as an identity record alongside the official paperwork your trip requires. You can read more about animal identity on the Animal Passport blog.

Common mistakes to avoid

• Buying by weight alone. Airlines check fit and posture, not just pounds.
• Trusting "IATA-approved" labels. IATA says it does not certify, approve, sell, or endorse any commercial container.
• Ignoring aircraft type. Delta says maximum in-cabin dimensions depend on the aircraft assigned to your flight.
• Overpacking the case. Toys and thick pads can push a dog's height past the internal limit.
• Using a sling in the car. An unrestrained or loosely held dog is not protected in a sudden stop.
• Skipping the rehearsal. A dog that has never been in the case is more likely to panic at the airport.

Bottom line

The best carrying case for dogs is the one sized from your dog's real measurements, built with enough ventilation for the strictest rule on your route, and matched to how you travel: soft and firm-framed for the cabin, rigid for the hold, independently crash-certified for the car. Rules change every year, so recheck IATA, your airline, and USDA APHIS within a few days of travel.

By Animal Passport. Last updated September 27, 2026.