Guide to Choosing a Kennel/Carrier

RespiratoryQ&AMeongsiljang Veterinary Advisory Board

We’ve put together a complete guide on how to choose the right type and size of carrier for dogs and cats, safety tips for air and car travel, and training methods to help your pet adjust.

Why Is a Carrier Important?

A dog and a cat sitting comfortably inside a carrier.

A pet carrier is a portable container used to safely transport dogs and cats during outings such as vet visits, travel, or moving. The most important thing is "security." Traveling to unfamiliar places can easily stress pets, and those unfamiliar with carriers or anxious about car rides tend to show more signs of fear, anxiety, and stress at the vet. Therefore, the carrier should not be a "scary place" but a safe space where your pet feels comfortable entering and staying on their own. The first step is choosing a product that is large enough for your pet to turn around comfortably and has adequate ventilation. For older pets or those with joint issues, it's best to allow a bit more extra space.

Types of Carriers — Hard, Soft, and Backpack

There are three main types available on the market.

Hard cases: Made of plastic, these are durable and impact-resistant. Many models are approved for air travel according to IATA standards.

Soft cases: Made of fabric and mesh, these are lightweight and ideal for short trips to the vet.

Backpack style: These are worn on the back, freeing up both hands, but they may not be suitable for long journeys.

The best type depends on your intended use (vet visits, travel, or air transport), so it’s best to choose based on the situation you’ll encounter most often.

Comparison by Type

Item	Hard case	Soft case	Backpack type
Durability	High	Medium	Medium
Air travel	True	False	False
Ventilation	Side holes	Mesh on 4 sides	Mesh on 3 sides
Ease of cleaning	Easy	Difficult	Moderate
Suitable travel distance	Long distance	Short distance	Short to medium distance

For cats and small dogs, a carrier whose top or side opens or detaches easily is best. During an exam, the vet can check your pet while it stays comfortably inside the carrier, which helps reduce stress and avoidance behavior.

How to Choose the Right Size?

The ideal carrier size should allow your pet to stand up and turn around comfortably. If it’s too large, your pet could be injured by sudden movements during abrupt stops; if it’s too small, it can strain their breathing and joints. - Small dogs and cats (up to 5 kg): Approximately 40 cm in width - Medium-sized (5–10 kg): 50–60 cm in width - Large-sized (10 kg and above): At least 70 cm in width For a more accurate fit, measure your pet’s shoulder height and body length rather than relying solely on weight. Always place a non-slip mat on the carrier floor.

An illustration showing how to measure the size of a carrier

What to Check Before Air and Car Travel

Airline regulations vary by carrier, so you should confirm the required specifications and make your reservation at least two weeks before departure. For in-cabin travel, the pet and carrier typically must weigh 7 kg or less and have combined dimensions (length + width + height) of 115 cm or less. When traveling by car, secure the carrier to the back seat with a seatbelt. Avoid placing the carrier on the passenger seat or your lap, as airbag deployment can be fatal.

5 Steps to Carrier Acclimation Training

The key is to help your pet view the carrier not as a scary place, but as a safe haven. Studies have shown that carrier acclimation training reduces stress associated with car rides and veterinary visits. 1. Keep the carrier in the living room with the door open as part of your everyday environment. 2. Place familiar blankets and treats inside to encourage your pet to enter on their own (never force them in). 3. Offer praise and treat rewards when they go inside. 4. Gradually practice closing and opening the door, starting with 5 seconds, then 30 seconds, and finally 3 minutes. 5. Progress from short car rides to longer trips through gradual exposure. Pets who already fear carriers, especially cats, require a slower, more delicate approach and may need more time to adapt. Avoid rushing; if your pet seems uncomfortable, step back to a previous stage where they felt at ease and proceed slowly.

Safety Checklist During Travel

These are the essential items to check right before and during travel.

Meals: Finish feeding 3–4 hours before departure (to prevent motion sickness)

Hydration: Attach a water bottle or provide 1–2 ice cubes

Ventilation: Use air conditioning for indirect air circulation instead of opening windows directly

Temperature: Maintain the car interior at 22–26°C; never leave your pet unattended in the car during summer

Identification: Attach a tag with your contact information and the pet’s registration number to the carrier

Emergency Contact: Save the contact details of a 24-hour veterinary clinic near your destination

An illustration showing a safety checklist for pet carriers

When to Postpone Travel

Transporting your pet can be dangerous in the following situations: - Within one week of surgery or anesthesia - During late pregnancy or within two weeks after giving birth - Brachycephalic breeds (Pugs, Bulldogs, Persians) when summer temperatures exceed 28°C (82.4°F) - Receiving oxygen therapy for heart or respiratory disease - Within 24 hours of seizures or vomiting If transportation is absolutely necessary, please consult your veterinarian first. Whenever possible, an in-home veterinary visit is the safer option.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Is it okay if my pet keeps barking or whining once inside the carrier?

It’s normal for your pet to show some initial reactions during the first few days. However, if the behavior persists for more than 30 minutes or if they’re drooling excessively, it could be a sign of stress. In that case, start the adaptation process over from the beginning, and consult your veterinarian if the symptoms are severe.

Which is better, a hard case or a soft case?

It depends on the purpose. For air travel, long-distance trips, or large dogs, a hard carrier is recommended. For short trips like vet visits, small dogs, or cats, a soft carrier or a top-loading hard carrier is more convenient. In particular, mesh soft carriers are highly practical because they allow veterinarians to administer sedatives or other injections through the mesh. Many pet owners own both types and choose the appropriate one based on the situation.

I’ve heard that top-loading carriers are the best for cats. Is that true?

That’s right. Cats experience less stress when they’re lifted out from the top rather than through a side door. A carrier that opens easily from both the top and the side allows veterinarians to perform an initial examination while your cat remains inside, which helps reduce avoidance behaviors.

What if your pet has an accident in the carrier?

It could be a temporary reaction due to stress. Place an absorbent pad on the floor, and keep extra pads and wet wipes on hand. If it happens repeatedly, it’s best to readjust the steps of the adaptation training.

My pet gets very motion sick inside the carrier. Is it okay to use medication?

There are medications that can help with severe motion sickness in vehicles. However, the type and dosage of medication depend on your pet's weight and health status, so it's essential to consult with a veterinarian and avoid self-administration. If motion sickness is severe, minimizing long-distance or repeated travel can also be a good approach.

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References

[1] Tizard, I.R., Comparative Mammalian Immunology, Academic Press, 2023

[2] Applied Veterinary Clinical Nutrition, 2nd Edition, Wiley-Blackwell

[3] IATA Live Animals Regulations (LAR), 50th Edition, 2024